Glossary of Investigation Terms and Legal Definitions

This collection of investigation definitions is intended to help private investigators, police officers and everyday citizens understand the meaning of various legal terms used by lawyers, attorneys, government officials, law enforcement departments, and other legal professionals.

Why These Terms are Important

During the course of their work, detectives will have interactions with police officers to discuss information contained in police reports; with attorneys and lawyers to discuss court cases and court records; and experts and specialists about such things as forensics, crime scene investigations and even handwriting analysis.

Having an understanding of the legal terms and the definitions will help private investigators “speak the language” of their craft. The more well-versed you become in the language of law, the more valuable you will become to your clients. Being able to translate legalese will help your clients feel more comfortable with you as a true expert investigator and you’ll be able to help guide them through the complexities of the legal system. It’s not your job to take the place of a qualified attorney, but you should be able to “talk the talk”.

List of Legal Terms and Definitions

Following is a list of some of the more commonly used terms and definitions. Click on a term in the list below to view the definition and recommendations for additional resources related to the term.

Our list of private investigation and legal terms is constantly growing, so please check back often. If you have a suggestion for a new definition, or have a question, please send us an email and we’ll do what we can to help.


Adultery is generally defined as the voluntary sexual intercourse between a married person and another person who is not their spouse. In the most basic sense, adultery is cheating on your spouse. In most cases, only the married party is said to have committed adultery.  If both parties are married (but not to each other) then they both have committed separate acts of adultery. Adultery is also referred to as: Extramarital sex, philandering, infidelity or cheating. In addition to cheating, other slang terms include creeping, “on the down low”, sleeping around, and others.

Adultery does not include fornication. The term “adultery” carries a moral or religious association, while the term “extramarital sex” is morally or judgmentally neutral. Many would consider that a married person has committed adultery by simply having impure thoughts, or confiding in a member of the opposite sex. Some consider that a married individual who has inappropriate chats with others online is guilty of being adulterous.


Arrests and Arrest Warrants

Assault and Battery


A bond is a written, binding agreement to perform something as specified.  Many different types of bonds exist and appear in marriage, land and court records used by genealogists. Historically, laws required administrators and executors of estates, grooms, and guardians of minors to post bonds.  If a bondsman failed to perform, the court may have demanded payment of a specified sum as a penalty. Private investigators should have an understanding of bonds, as they will undoubtedly have to deal with different types of bonds during the course of their work. Investigators who offer bounty hunting services will need to be familiar with bail bonds and bail bondsmen. There will be a bail bond associated with every fugitive you are hired to track and retrieve. In addition, detectives will themselves need to be bonded as a part of the licensing requirements in most, if not every state. In this situation, it serves as insurance for a third party, such as state in which the private eye is licensed. It serves as a way of insuring that the licensed individual properly complies with state laws, statutes and rules and regulations of their trade. The cost of obtaining a bond varies from state to state, term periods, coverage amounts and whether you are an individual or a full-service agency. Do a Google search to find local companies that offer insurance services in this area. See also Bail Bonds and Bail Bondsman.


Burglary is a crime that is defined as the illegal entry into a building or home for the purposes of committing an offense or committing a crime. Usually the offense committed during burglary is the theft of property. Burglary is one of the most common crimes in the United States. Individuals burglarize homes, cares, businesses, storage units, and more. Stolen items are often sold at pawn shops or via online marketplaces such as eBay. The crime of burglary consists of two elements: trespass and breaking. The trespass element indicates the an individual’s presence on the property (car, storage unit, etc.) is without the owner’s consent. In other words the thief did not have permission to enter. The breaking element consists of making an opening to enter the building. To commit a burglary is to burgle or to burglarize. Other common names for burglary include: Breaking and entering, Housebreaking, Break-in, Home invasion.

The punishment for burglary is usually imprisonment. The term of the imprisonment depends on the degree of severity of the burglary. Greater penalties are given if the burglary involved deadly weapons or if persons were injured as a result of the crime.

Citizen’s Arrest

Class Action Lawsuit

In a legal sense, a class action lawsuit is a form of suit in which a large group of people collectively bring a claim to court and/or in which a class of defendants is being sued.  This type of legal action originated in the United States. However, in several European countries, changes have been made to the legal system to allow consumer organizations to bring claims on behalf of large groups of consumers, similar to the processes used in the U.S..

Class action lawsuits are most often seen in relation to pharmaceuticals and drug companies, usually related to injuries or deaths associated with a particular product or drug. In other cases, many public companies face class action suits related to the trading of their stock and dividend matters.

Class action lawsuits may appear to offer an advantage to individual plaintiffs because they aggregate a large number of individualized claims into one representational lawsuit. However, if a lawsuit is won against the defendant, the plaintiffs in the case usually only receive a very small amount of compensation. It is usually the attorneys and legal teams that end up making millions. Many people who receive a notice of a class action lawsuit in the mail do not complete the steps necessary to make a claim. The attorneys and lawyers involved in the process make the claims process confusing and laborious, seemingly in an attempt to reduce the number of claims made by individuals. This results in a larger pot of money for others, including the legal group involved in administering the suit.

These types of lawsuits are generally viewed as an important and valuable part of the legal system when they permit the fair and efficient resolution of legitimate claims of numerous parties by allowing the claims to be aggregated into a single action against a defendant that has allegedly caused harm.

However, the typical class action suits end up benefiting the attorneys who file the suit. The burden is often placed on the individual to file a claim and provide proof of wrongdoing. Sometimes the burden is so great, that individuals don’t bother completing the requirements of the class action suits. This ultimately ends up padding the pockets of the attorneys.


In criminal law, a conspiracy is defined as an agreement between two or more persons to break the law at some time in the future. In other words, they “conspire” to commit a crime together.  In some cases, a conspiracy requires there to be at least one overt act in furtherance of the agreement to commit a crime. Examples of such acts of furtherance include the purchase of supplies or materials, visiting or “scoping” the location, or documenting plans for the act. However, in most countries, there is no requirement that any steps be taken to put the conspiracy plan into effort for it to be considered unlawful.

There is no limit on the number of people who might participate in the planning or execution of the conspiracy. In some situations, only two people are required to qualify. In others, small groups or even organized gangs may be involved. In other situations, entire organizations or even military organizations could be involved in the planning and execution of the act. Conspiracies can take place in relation to any situation. In some cases, the conspiracy may be harmless. Such as a group of employees who conspire to pull a practical joke on a co-worker. However, in most situations, conspiracies are considered to be of a sinister nature and intended to cause harm. Most conspiracies are centered around anti-government or anti-military behavior.

Copyright Infringement

Copyright infringement (or copyright violation) is the unauthorized use of material that is covered by copyright law, in a manner that violates one of the copyright owner’s exclusive rights, such as the right to reproduce or perform the copyrighted work, or to make derivative works. For electronic and audio-visual media, unauthorized reproduction and distribution is occasionally referred to as piracy.

If you need to research copyright laws, the best place to start is the U.S. Copyright Office. The U.S. Copyright Office website is an excellent resource for learning and understanding copyrighting and related laws.  The United States Copyright website provides an overview of copyright basics, information on the law, and a list of FAQs.  You can also Search the Catalog of records of registered books, music, art, and periodicals, and other works. Includes a review of ownership documents. Private investigators are sometimes hired to investigate such cases. A detective’s primary role in such cases is to gather evidence and proof of infringement.

Crimes and Torts


Defendants on Plaintiffs


Detention, or detaining, of suspects is the process of keeping a person who has been arrested in a jail cell, prison or other detention center before their legal trial or sentencing. Such buildings are often referred to as detention centers or detention facilities. People can also be detained illegally or against their will. In this situation, crimes such as kidnapping or unlawful arrest may occur. Private detectives may deal with cases that involved individuals that have been detained. Detectives may need to travel to prisons, county jails or other detention facilities to interview witness and suspects to gather information for a case. In some situations, a private detective may need to physically restrain an individual until the police or other law enforcement officials arrive. This is a rare circumstance, but it certainly does happen. It is important to note that a private eye does not have any powers of arrest. See also Kidnapping.





False imprisonment

False imprisonment is a tort, and possibly a crime. It involves a situation where a person or multiple persons are intentionally confined by another person or persons without legal authority. It entails the restraint of an individual or the obstruction of their freedom without their consent. The imprisonment of another can take many forms, such as:

  • Being tied to a chair or other immovable object
  • Being locked in a room
  • Being locked in a car
  • Being physically held or restrained

The elements of false imprisonment usually involves:

  • The person detained is being held against their will
  • The imprisoned person is unable to move about freely
  • Proof can be provided that the imprisonment was not lawful

False imprisonment can be applicable to private situations as well as government.

Although punishment may vary from country to country, and even state to state, it is generally considered to be a 3rd degree felony, which carries penalties such as: Up to five years in jail, a fine of up to $5,000, probation, community service, other penalties as defined by the court. If false imprisonment can be proved, damages may be awarded in civil court.

The term false arrest is sometimes used in relation to false imprisonment, but it actually has a different meaning. Under a false arrest, one person arrests another, but the arresting person does not have legal justification or legal authority to do so. If the arresting person takes the other into custody and restricts their freedom, then it also becomes false imprisonment.

Family Law

Family Law – Includes an overview of Alimony, Child Support and Legal Guardianship

Grand Larceny

Grand larceny is the crime of theft of another’s property (including money) that exceeds a certain value (for example, $500). Grand larceny is distinguished from petty (or petit) larceny in which the value is below the grand larceny limit. Some states only recognize the crime of larceny, but draw the line between a felony (punishable by state prison time) and a misdemeanor (local jail and/or fine) based on the amount of the money.

Judges and Juries

Juvenile Delinquency




Larceny is a form of theft. Larceny involves the taking and carrying away of personal property without the owner’s consent. The terms ‘petty larceny’ and ‘grand larceny’ refer to the value of items that were taken.



A lawsuit is a civil action brought in a court of law in which a plaintiff, a party who claims to have incurred loss as a result of a defendant’s actions, demands a legal or equitable remedy. The defendant is required to respond to the plaintiff’s complaint. If the plaintiff is successful, judgment will be given in the plaintiff’s favor, and a variety of court orders may be issued to enforce a right, award damages, or impose a temporary or permanent injunction to prevent an act or compel an act.  A declaratory judgment may be issued to prevent future legal disputes. A lawsuit may involve dispute resolution of private law issues between individuals, business entities or non-profit organizations. A lawsuit may also enable the state to be treated as if it were a private party in a civil case, as plaintiff or defendant regarding an injury, or may provide the state with a civil cause of action to enforce certain laws.

  • The conduct of a lawsuit is called litigation
  • One who has a tendency to litigate rather than seek non-judicial remedies is called litigious

Misdemeanors and Felony Crimes

Mug Shots

  • Mug Shots – Photos taken of arrested individuals

Nolo Contendere

Nolo contendere is a Latin legal term that simply stands for “I do not wish to contend.”  Nolo contendere is also referred to as a plea of “no contest” and is often referred to as “pleading nolo.” In criminal court trials, Nolo contendere is a legal plea made by the defendant who does not admit to committing a criminal charge, nor do they dispute the charge. Entering such a please is considered to be an alternative to pleading to be specifically guilty or not guilty to the criminal charge.

A no-contest plea, which is technically not a guilty plea, is often offered as a part of a plea bargain deal from the prosecutor. It is not always an option to enter such a plea. The state law in which the crime was committed will determine whether the defendant may plead no contest in criminal court cases, so consult your state and local laws to confirm. For more information on the topic, visit


Paralegal is a term used to describe people who assist lawyers in their legal work. The profession originated as an assistant or secretary who provided assistance to lawyers with legal matters, research and related matters. Paralegals are not lawyers, but generally do have knowledge, education and even certification in legal matters and law.

  • Paralegals are not authorized by the government to offer legal services such as those provide by an attorney or lawyer
  • They are not considered to be officers of the court (i.e. considered a formal part of the legal system)
  • They are not usually subject to government or court-sanctioned rules of conduct
  • They work under the direct supervision of a lawyer

Although most jurisdictions recognize paralegals, there is no international consistency regarding the definition, role, status, terms and conditions of employment, paralegal training, regulation or anything else and so each jurisdiction must be looked at individually.


Perjury is basically lying in court. Perjury is officially defined as the willful act of swearing a false oath or affirmation to tell the truth concerning matters material to a judicial proceeding.  The act of perjury can be either spoken or written, but is most commonly committed as part of spoken testimony in a court case.

During court proceedings that involve witnesses, each witness that testifies must swear under oath that they will tell the honest truth. Oaths are taken during court in front of the judge and often in front of a jury. Witnesses are not forced or coerced to take the oath, but it is required. When a witness commits perjury, they falsely promise to tell the truth about matters which affect the outcome of the case.

The exact wording of the oath may vary from country to country, and even from state to state. Following is an example of the typical oath used in the United States: “Do you solemnly swear or affirm that you will tell the truth, the whole truth, and nothing but the truth, so help you God?” The court bailiff usually swears in the witness and the witness usually places their hand on a bible as they agree to the oath.

When a person is charged and convicted of perjury, they may face criminal charges in the form of a financial fine or, in more serious cases, may serve jail time. Each state has their own laws and penalties regarding this crime.

Petty Larceny

Petty larceny is a term used in many states for theft of a small amount of money or items that have little value (such as less than $500). Petty larceny is considered to be a misdemeanor and is usually punishable at maximum with a term in the county jail. States which only use the term “larceny,” often treat theft of a smaller amounts as a misdemeanor in sentencing.


Search and Seizure

Search Warrant

  • Search Warrant – Permission to search a vehicle, house or other property

Sexual Assault


In the United States, solicitation is the name of a crime that consists of a situation where a person offers money or something else of value in order to incite or induce another to commit a crime with the specific intent that the person solicited commit the crime. Basically, it is convincing someone else to do something illegal. This can be accomplished in a variety of ways. Other definitions of Solicitation include: To entice or incite to take evil or illegal action; To approach or accost (a person) with an offer of sexual services; To make solicitation or petition for something desired; To approach or to accost someone with an offer of sexual services in return for financial. Situations involving solicitation are most common in relation to prostitution. Prostitutes are said to have “solicited” sex.


A statement is a formal account of the facts related to a case. A statement is given by a witness, defendant or other party related to a case in a court of law.

Statute of Limitations

A statute of limitations is a legal statute in that sets forth the maximum period of time, after certain events have occurred, that legal proceedings based on those events may be initiated. Basically, what this means is that after a certain length of time, you may not be able to sue someone in a court of law if the limitation has been exceeded. Also, someone may not be prosecuted for a crime after the period has expired. In civil law systems, similar provisions are usually part of the state, city or county civil code or the criminal code and are often known collectively as “periods of prescription” or also “prescriptive periods.” Statutes vary from state to state and depend on the particular situation, so check your local laws to determine what applies in the area in which your case resides.


  • Summons (also known as subpoenas)



Legal testimony – legal testimony is a form of evidence that is obtained from a witness who makes a solemn statement or declaration of fact. Testimony may be oral or written, and it is usually made by oath or affirmation under penalty of perjury. Unless a witness is testifying as an expert witness, testimony in the form of opinions or inferences is generally limited to those opinions or inferences that are rationally based on the perceptions of the witness and are helpful to a clear understanding of the witness’ testimony.

Expert testimony – An expert witness provides their opinion about facts and conclusions within their field of expertise.

Private investigators are sometimes called upon to testify in a court of law. They may be summoned to provide evidence and testimony regarding information they uncovered during the course of an investigations. Private eyes find themselves testifying in court in relation to divorce investigations and marital infidelity.


Theft, in its simplest terms is stealing. Theft occurs when a person takes, or steals, property or items that do not belong to them.  Theft is often used as an informal term for crimes against property, such as:

  • Burglary– usually involves breaking into someone’s home or car and stealing items
  • Embezzlement– occurs when individuals steal money or property from a business, usually a business they work for
  • Larceny– Taking another persons property away
  • Looting – occurs most often during times of natural disaster or rioting, where individuals enter homes or businesses and remove items or property that does not belong to them
  • Robbery – this type of theft usually occurs at gun point, or with the threat of harm
  • Shoplifting – occurs when property is illegally removed from a business
  • Fraud – fraud usually involves a plot or scheme to steal money or property from an individual or a group of people
  • Criminal conversion

In some jurisdictions, theft is considered to be synonymous with larceny; in others, the crime of theft has replaced that of larceny. Someone who carries out an act of or makes a career of theft is known as a thief. The act of theft is known by many other terms, such as stealing, robbing, and jacking.

Wire Tapping

Related Information

  • If you need legal forms related to any of the above, see a full list of legal forms at
  • Also, see our list of Acronyms related to the legal field, law enforcement and the investigation industry.

Online Dictionaries and Glossaries for Research

Private investigators spend a large proportion of their time conducting research, both in the physical sense and in searching for information and data.  Understanding the origin, meaning and pronunciation of words will help you become more adept at conducting research.

That is where online dictionaries and glossaries come in handy. Online dictionaries and glossaries are designed to make it easy to quickly look up words, find the meaning, associated words, synonyms, antonyms, rhyming words, and more more. Nearly everything there is to know about a word, it’s origin and history is available via a quick online search. Also, many of the more popular sites have software apps that put the data right at your fingertips.

Following are online dictionaries and glossaries for looking up words, acronyms, abbreviations and more.

  • Acronym Finder – The Acronym Finder is a searchable database of more than 369,000 abbreviations and acronyms about computers, technology, telecommunications, and military acronyms and abbreviations.
  • CEO Express – Executive Gateway to the Internet. Provides a large number of categorized links to a wide variety of resources.
  • Dictionary: One Look – One Look dictionary search tool. Use this tool to find the meaning of words.
  • Information Please – Information Please is part of Pearson Education, the largest educational publisher in the world and owner of Prentice Hall, Scott Foresman, Addison Wesley Longman, and other distinguished imprints. Pearson also owns Athe Financial Times and Penguin Putnam publishers.
  • Internet Library for Librarians – Internet Library for Librarians provides links to more than 4,000 resources. All the resources are recommended, selected, and reviewed by librarians. Each entry has a full description of the goals and /or scope of the resource, as well as the contact information if provided. Internet Library for Librarians is a handy and useful tool for both novices and experienced library staff.
  • Investor Words – Launched in 1999, InvestorWords is the premier financial glossary on the web, helping millions of individuals understand and keep up-to-date with the terms that they need to know in order to succeed in today’s financial world.
  • Marketing Dictionary – Internet marketing reference and index of the best sites & articles
  • Merriam-Webster Dictionary – Merriam-Webster is America’s foremost publisher of language-related reference works. The company publishes a diverse array of print and electronic products, including Merriam-Webster’s Collegiate® Dictionary, Eleventh Edition—America’s best-selling desk dictionary—and Webster’s Third New International Dictionary, Unabridged.
  • Resource Centers – Library of Congress research and reference information. The Library of Congress is the nation’s oldest federal cultural institution and serves as the research arm of Congress. It is also the largest library in the world, with millions of books, recordings, photographs, maps and manuscripts in its collections.
  • Technical Dictionary –® is a knowledge exploration and self-education tool about information technology, especially about the Internet and computers. It contains over 4,500 individual encyclopedic definition/topics, a number of “Fast Reference” pages and learning tools. The topics contain about 12,000 hyperlinked cross-references between definition-topics and to other sites for further information. The site is constantly updated.
  • Thesaurus – is produced by Lexico Publishing Group, a leading provider of language reference products and services on the Internet.  To use the thesaurus, simply type a word in the gold search box and click the ‘Search’ button. A list of synonyms and antonyms will be returned.
  • Webopedia – The only online dictionary and search engine you need for computer and Internet technology definitions.
  • Your Dictionary – is a language products and services company that maintains the most comprehensive and authoritative language portal on the web with more than 2500 dictionaries and grammars in over 300 languages, games that build language skills, and a forum (The Agora) for discussing language issues with the logophile community.


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