This legal terminology glossary defines the words you are most likely to encounter in a contract, a courtroom, a police interaction, or a probate file. Most of these terms come from Latin or old French and have survived because plain English does not have a tidy replacement for the idea. Each definition below sticks to what the word actually means and how it works in practice.
Who’s Who in a Lawsuit
Plaintiff. The person or company claiming they were harmed and asking the court for a remedy.
Defendant. The person or company being accused. In a criminal case the government fills the plaintiff’s role as prosecutor, but the person charged is still called the defendant. Once served, the defendant has a limited window to respond, and the exact deadline depends on the type of case and how the papers were delivered.1Judicial Legal Help Center. Answering a Civil Case
Pro se. A party who handles their own case without hiring a lawyer. Federal law expressly allows parties to plead and conduct their own cases in any U.S. court.2Office of the Law Revision Counsel. 28 USC 1654 – Appearances Personally or by Counsel Judges still hold pro se litigants to essentially the same procedural rules as attorneys.
Jurisdiction. The court’s legal authority to make binding decisions. It has two layers: personal jurisdiction over the parties, and subject-matter jurisdiction over the type of dispute. A federal court hearing a tax case has subject-matter jurisdiction over federal tax law, but still needs a valid basis for authority over each party.
Service of process. The procedure for formally delivering a summons and complaint to the defendant. The Constitution’s due process protections prohibit a court from exercising authority over someone who never received proper notice of the lawsuit.3Legal Information Institute. Service of Process Personal hand-delivery by a process server is the most common method. If a defendant dodges service, courts allow alternatives like posting notice or publication in a newspaper, though those methods face a higher bar for approval.
Discovery Terms
Discovery is the pre-trial phase where both sides exchange information. The evidence that surfaces here often drives settlements and shapes trial strategy.
Affidavit. A written statement of facts signed under oath, typically in front of a notary public. Lying in one carries the same penalties as lying on the witness stand, which is why courts treat affidavits as evidence.
Unsworn declaration. A federal alternative to an affidavit. The signer writes “under penalty of perjury” instead of appearing before a notary, and the document carries the same legal weight as a sworn affidavit.4Office of the Law Revision Counsel. 28 USC 1746 – Unsworn Declarations Under Penalty of Perjury
Deposition. Live, out-of-court testimony given under oath. A witness answers attorneys’ questions while an officer records everything, and the testimony can later be used to contradict a witness who changes their story at trial.5Legal Information Institute. Federal Rules of Civil Procedure Rule 32 – Using Depositions in Court Proceedings The examination follows essentially the same format as questioning at trial.6Legal Information Institute. Federal Rules of Civil Procedure Rule 30 – Depositions by Oral Examination
Interrogatories. Written questions one party sends to the other, with answers given in writing under oath. Federal rules cap these at 25 per party unless a judge allows more.7Legal Information Institute. Federal Rules of Civil Procedure Rule 33 – Interrogatories to Parties
Requests for production. Formal demands that the other side hand over specific documents or items, from emails to financial records. The responding party generally has 30 days to comply or raise objections.8Legal Information Institute. Federal Rules of Civil Procedure Rule 34 – Producing Documents, Electronically Stored Information, and Tangible Things
Work product. Materials an attorney prepares while getting ready for litigation. Notes, legal theories, draft memos, and strategy outlines are shielded from discovery. The protection is not absolute: a court can order disclosure if the requesting party shows a substantial need and no other reasonable way to get the information.
Standards of Proof
The standard of proof tells the jury or judge how convinced they need to be before ruling in one side’s favor.
Preponderance of the evidence. The default standard in most civil cases. You win if the evidence tips the scale even slightly in your favor, meaning your version is more likely true than not.
Clear and convincing evidence. A higher bar used in cases like fraud, will contests, and civil commitment proceedings. The evidence must leave the decision-maker with a firm belief that the claim is highly probable.9Ninth Circuit District and Bankruptcy Courts. Burden of Proof – Clear and Convincing Evidence
Beyond a reasonable doubt. The highest standard in the legal system, reserved for criminal cases. The prosecution must present evidence strong enough to leave jurors firmly convinced of guilt.
The gap between civil and criminal standards matters in practice. A defendant can be acquitted in a criminal trial yet still lose a civil lawsuit over the same facts, because the plaintiff only has to show their version is more probable.
Civil Case Vocabulary
Civil cases are disputes between private parties where the typical remedy is money or a court order rather than jail time.
Tort. A civil wrong that causes someone harm. Slip-and-fall injuries, defamation, and medical malpractice all qualify.
Liability. The legal conclusion that a party is responsible for harm and must pay for it.
Compensatory damages. Money meant to restore you to where you were before the harm, covering medical bills, lost income, and property repair costs.
Punitive damages. An additional penalty reserved for especially reckless or malicious behavior. These go beyond making the victim whole and exist to punish the defendant and discourage similar conduct. The Supreme Court has held that few punitive awards exceeding a single-digit ratio to compensatory damages will satisfy constitutional limits.10Justia U.S. Supreme Court. State Farm Mutual Automobile Insurance Co v Campbell, 538 US 408 (2003)
Injunction. A court order requiring someone to do something or stop doing something. Courts grant injunctions when money would be inadequate and the plaintiff faces irreparable harm. A preliminary injunction can freeze the situation during the case; a permanent injunction becomes part of the final judgment.
Summary judgment. A ruling that ends a case before trial because the judge finds no genuine factual dispute left to resolve and the law clearly favors one side.11Legal Information Institute. Federal Rules of Civil Procedure Rule 56 – Summary Judgment
Settlement. An agreement where both sides resolve the dispute on their own terms, usually in exchange for a payment and a release.
Release. A contract in which the plaintiff gives up the right to sue over the same matter again. Signing one without reading carefully can waive claims you did not realize you had.
Res judicata. Also called claim preclusion. It bars you from filing a second lawsuit based on the same dispute once a court has issued a final judgment on the merits.12Legal Information Institute. Res Judicata
Collateral estoppel. Also called issue preclusion. It prevents relitigating a specific factual or legal question that was already decided, even if the second lawsuit involves a different overall claim.13Legal Information Institute. Collateral Estoppel
Criminal Case Vocabulary
Misdemeanor. A less serious crime punishable by fines, probation, or jail time of less than one year.
Felony. A more serious offense carrying potential imprisonment of more than one year in a state or federal prison. Felony convictions can also strip voting rights, disqualify you from certain jobs, and affect custody decisions.
Indictment. A formal charging document issued by a grand jury after it reviews the prosecution’s evidence and determines there is probable cause to believe a crime was committed.14United States Department of Justice. 9-11.000 – Grand Jury Not every criminal charge goes through a grand jury; less serious cases often begin with a criminal complaint filed by a prosecutor.
Arraignment. The defendant’s first formal court appearance. The judge reads the charges, the defendant enters a plea of guilty or not guilty, and the court addresses bail and appointment of counsel for anyone who cannot afford a lawyer.15United States Department of Justice. Initial Hearing / Arraignment
Acquittal. A finding of not guilty at the end of a trial.
Double jeopardy. The Fifth Amendment protection providing that no person shall “be subject for the same offence to be twice put in jeopardy of life or limb.”16Constitution Annotated. Amdt5.3.1 Overview of Double Jeopardy Clause The government cannot retry someone after an acquittal, even if the acquittal was the result of a legal error by the trial judge.17Constitution Annotated. Amdt5.3.6.1 Overview of Re-Prosecution After Acquittal
Miranda rights. The warnings police must give before custodial interrogation: the right to remain silent, the warning that anything you say can be used against you, the right to a lawyer, and the right to a court-appointed lawyer if you cannot afford one.18Justia U.S. Supreme Court. Miranda v Arizona, 384 US 436 (1966) These warnings are required only during custodial interrogation, meaning you are not free to leave and police are asking questions designed to elicit incriminating answers. Statements obtained without a proper warning are generally inadmissible at trial. Once you invoke silence or ask for an attorney, questioning must stop until counsel is present.19Legal Information Institute. U.S. Constitution Annotated – Requirements of Miranda
Attorney-Client Privilege
Confidential communications between you and your lawyer are protected by attorney-client privilege. The privilege belongs to you, which means only you can waive it. For a conversation to qualify, it must relate to your seeking legal advice and must be kept confidential. Having a friend sit in on the meeting or forwarding your lawyer’s email to a colleague can destroy the protection.
The privilege does not cover everything. If you consult a lawyer to plan a crime or commit fraud, the conversation is not protected. The privilege can also be waived inadvertently, though federal rules provide a safety net: if the disclosure was accidental, you took reasonable steps to prevent it, and you acted quickly to fix the error, the privilege may survive.
Lawyers also owe a duty of candor to the court. An attorney cannot knowingly present false evidence or let the court rely on a lie, even if correcting the record conflicts with the client’s wishes.20American Bar Association. Rule 3.3 Candor Toward the Tribunal
Contract Terms
Consideration. Something of value exchanged by each side, which is required for a contract to be enforceable. It can be money, goods, services, or even a promise not to do something you have a legal right to do. A promise to make a gift generally is not enforceable because it lacks consideration.
Breach. A failure to perform contractual obligations without a valid excuse. Breaches range from minor (a late delivery that causes no real harm) to material (a failure so serious it defeats the entire purpose of the agreement). A material breach can justify the other party in walking away and suing for damages.
Force majeure. A clause excusing performance when extraordinary, unforeseeable events make it impossible. Natural disasters, wars, pandemics, and government shutdowns are the typical triggers. Vague language invites disputes; the more specific the clause, the easier it is to enforce.
Indemnity. A provision shifting risk from one party to the other. If you agree to indemnify a business partner, you are promising to cover their losses if certain problems arise, such as third-party lawsuits or regulatory fines. Indemnity clauses can expose you to costs far beyond the value of the contract itself.
Statute of frauds. A long-standing rule requiring a signed written record for certain contract categories, including real estate transfers, agreements that cannot be completed within one year, and sales of goods above a specified dollar threshold. A handshake deal for the sale of a house is not enforceable in court. The writing does not have to be a formal contract, but it must contain enough detail to show both parties intended to create an agreement and must be signed by the party you are trying to hold to it.
Filing Deadlines
Statute of limitations. A legal deadline for filing a lawsuit or bringing criminal charges. Miss it, and your claim is dead regardless of how strong the evidence is. Deadlines vary widely by case type and jurisdiction. Personal injury claims often carry deadlines of two to three years; contract disputes may allow four to six. Some federal enforcement actions must be brought within five years of when the claim first arose.21Office of the Law Revision Counsel. 28 USC 2462 – Time for Commencing Proceedings
Tolling. A doctrine that pauses the limitations clock, typically when the injured person is a minor, is mentally incapacitated, or when the defendant has left the jurisdiction.
Discovery rule. A doctrine that delays the start of the limitations deadline until the injured person knew or reasonably should have known about the harm. Medical malpractice and toxic exposure cases rely on it heavily, because the injury may not become apparent for years. Neither tolling nor the discovery rule helps someone who simply forgot to file or chose to wait.
Estate and Probate Terms
Probate. The court-supervised process of validating a will, settling debts, and distributing assets. If the deceased left a valid will, the court appoints the person named in it (the executor) to manage the estate.
Intestate. Dying without a will. State law then dictates who inherits, generally prioritizing spouses and children, then parents and siblings. The results often differ from what the deceased would have wanted.
Beneficiary. Any person or organization named in a will, trust, or insurance policy to receive assets or benefits. A single estate can have dozens, each receiving different property or amounts.
Codicil. A separate document that modifies specific portions of an existing will. Codicils must meet the same formal requirements as the will itself, including witnesses and signatures, so many attorneys now recommend drafting a new will rather than layering amendments.
Fiduciary duty. The legal obligation an executor, trustee, or estate administrator owes to the beneficiaries. The core duties are loyalty (no self-dealing or conflicts of interest), care (prudent management of assets), impartiality (fair treatment of all beneficiaries), and transparency (accurate records and accountings). A breach can result in personal liability for any losses the beneficiaries suffer, removal from the role, and in extreme cases, criminal prosecution.