Basic Terminologies in Law (US): Common Legal Terms Explained

Disclaimer: “This is general legal information for the United States, not legal advice. Laws vary by state and facts matter.”

Quick Summary

Legal documents and court forms often use words that sound formal but have specific meanings. This guide explains basic legal terminology you’ll commonly see in U.S. courts, civil disputes, criminal cases, and contracts—using plain English and practical examples. For official court definitions, see the federal judiciary glossary from the Administrative Office of the U.S. Courts: U.S. Courts—Glossary of Legal Terms.

Key takeaway: Many terms are used nationwide, but deadlines, procedures, and even court names can differ by state and by court system (state vs. federal). Start with your court’s self-help website for local rules and forms.

Key Definitions

People and roles in a case

• Party: A person or organization directly involved in a case (for example, a plaintiff or defendant). (Source: U.S. Courts Glossary)
• Plaintiff: The person or entity who starts a civil case by filing a complaint. (Source: U.S. Courts Glossary)
• Defendant: The person or entity being sued in a civil case, or the person accused in a criminal case (context matters). (Source: U.S. Courts Glossary)
• Prosecutor: The government’s attorney in a criminal case. (Source: DOJ—Justice 101 Glossary)
• Public defender: A lawyer who may represent people accused of crimes who cannot afford a private attorney (eligibility varies by jurisdiction). (Source: DOJ—Justice 101 Glossary)
• Judge: A court official who oversees a case and rules on legal issues; the judge may also decide the case in some situations. (Source: U.S. Courts Glossary)
• Jury: A group of community members that may decide the facts in a trial in some cases. (Source: U.S. Courts Glossary)

Where a case can be filed

• Jurisdiction: A court’s power to hear a case and issue orders, and/or the geographic area where the court can exercise authority. (Source: Cornell LII—Wex: Jurisdiction)
• Subject-matter jurisdiction: A court’s authority to hear a particular type of case. (Source: Cornell LII—Wex: Subject-Matter Jurisdiction)
• Venue: The proper geographic location/court where a case should be heard; wrong venue can create procedural problems. (Source: Cornell LII—Wex: Venue)

Common mistake: Mixing up jurisdiction (power to hear a case) with venue (the correct location for the case). (Sources: Jurisdiction, Venue)

Starting (and responding to) a civil case

• Complaint (civil): The document the plaintiff files to start a lawsuit, explaining what happened and what the plaintiff wants the court to do. (Source: U.S. Courts Glossary)
• Answer: The defendant’s formal written response to a civil complaint. (Source: U.S. Courts Glossary)
• Service of process: The formal delivery of court papers (like a summons and complaint) under court rules, so the other party is notified. (Source: Utah Courts—Glossary)

Common court filings and documents

• Motion: A request asking the court to do something (for example, dismiss a claim or compel an action). (Source: U.S. Courts Glossary)
• Affidavit: A written statement made under oath. (Source: New York Courts—Glossary (PDF))
• Brief: A written document explaining a party’s legal arguments and supporting facts. (Source: DOJ—Justice 101 Glossary)
• Order: A direction issued by the court (for example, setting deadlines or requiring specific actions). (Source: U.S. Courts Glossary)
• Judgment: The court’s official decision that resolves the case (sometimes after a trial, sometimes after motions). (Source: U.S. Courts Glossary)

Evidence and fact-finding

• Evidence: Information used to prove or disprove facts in a case (documents, testimony, photos, recordings, and more). (Source: NIJ—Law 101 Glossary)
• Discovery: A pretrial process where parties gather information to prepare for a hearing or trial (rules vary by court). (Source: Cornell LII—Wex: Discovery)
• Subpoena: A command issued under a court’s authority requiring a witness to appear and give testimony (and sometimes provide documents, depending on the subpoena). (Source: U.S. Courts—Subpoena)

How cases can end (with or without trial)

• Settlement: An agreement between parties resolving a dispute, often without a trial. (Source: U.S. Courts Glossary)
• Alternative Dispute Resolution (ADR): Ways to resolve disputes outside a trial, such as mediation and arbitration. (Source: U.S. Courts Glossary)
• Appeal: A request for a higher court to review a lower court’s decision. (Source: DOJ—Justice 101 Glossary)

Core civil-law concepts

• Tort: A civil wrong (an act or omission) that causes injury or harm and may lead to legal liability. (Source: Cornell LII—Wex: Tort)
• Negligence: Failing to act with the level of care a reasonable person would use under similar circumstances. (Source: Cornell LII—Wex: Negligence)
• Contract: An agreement creating obligations that can be enforceable by law. (Source: Cornell LII—Wex: Contract)
• Damages: Money a court may award for a legal wrong (types and limits can depend on the claim and jurisdiction). (Source: U.S. Courts Glossary)
• Injunction: A court order directing someone to do something or stop doing something, often used when money alone is not enough to address the harm. (Source: Cornell LII—Wex: Injunction)

Core criminal-law concepts

• Probable cause: A legal standard used in criminal procedure (for example, for certain warrants), based on facts indicating a reasonable basis to believe a crime occurred. (Source: DOJ—Justice 101 Glossary)
• Arraignment: A proceeding where a person accused of a crime is told the charges and asked to enter a plea. (Source: DOJ—Justice 101 Glossary)
• Plea: The defendant’s response to criminal charges (such as guilty or not guilty). (Source: DOJ—Justice 101 Glossary)
• Burden of proof: The standard a party must meet to prove a fact in court; standards differ by situation. (Source: Cornell LII—Wex: Burden of Proof)
• Beyond a reasonable doubt: The burden of proof required for a criminal conviction. (Source: Cornell LII—Wex: Beyond a Reasonable Doubt)

What varies by state?

• Deadlines (statutes of limitations): Time limits to file many claims vary by jurisdiction and type of case. (Source: Cornell LII—Wex: Statute of Limitations)
• Court structure and court names: For example, “district court” can mean different things in different states.
• Procedures and local rules: Filing rules, formatting, service requirements, motion practice, and court forms can differ by court and location (even within the same state).

To avoid confusion, use your court’s official self-help website (state courts) or the federal judiciary website for federal courts. (Source: U.S. Courts Glossary)

How a typical civil case moves through court (high level)

1. Complaint filed by the plaintiff. (Source: U.S. Courts Glossary)
2. Service of process delivers papers under court rules. (Source: Utah Courts—Glossary)
3. Answer filed by the defendant (or another response allowed by court rules). (Source: U.S. Courts Glossary)
4. Motions ask the court for rulings. (Source: U.S. Courts Glossary)
5. Discovery to gather information before trial. (Source: Cornell LII—Wex: Discovery)
6. Settlement talks or ADR may happen at any point. (Source: U.S. Courts Glossary)
7. Trial (if the case doesn’t settle), then judgment. (Source: U.S. Courts Glossary)
8. Appeal may be available in some cases. (Source: DOJ—Justice 101 Glossary)

Note: This is a simplified overview. The actual path depends on the court, the type of claim, and procedural rules.

Common mistakes and confusion points

• Confusing legal standards: “Burden of proof” depends on the type of case and issue. (Source: Cornell LII—Wex: Burden of Proof)
• Assuming deadlines are the same everywhere: Statutes of limitations vary by jurisdiction and claim type. (Source: Cornell LII—Wex: Statute of Limitations)
• Ignoring court paperwork: Documents like complaints, orders, and subpoenas can create obligations or deadlines. (Sources: U.S. Courts Glossary, U.S. Courts—Subpoena)

When to consult a lawyer

• If you face criminal charges or potential loss of liberty.
• If there are fast-approaching deadlines (filing dates, hearings, statutes of limitations). (Source: Cornell LII—Wex: Statute of Limitations)
• If you received formal court paperwork (a complaint, subpoena, or court order) and do not understand what it requires. (Sources: U.S. Courts Glossary, U.S. Courts—Subpoena)

Where to get help and reliable information

• USA.gov (legal aid): Government starting point for finding free/low-cost legal help. (Source: USA.gov—Legal Aid)
• Legal Services Corporation (LSC): Locate LSC-funded civil legal aid organizations by area. (Source: LSC—I Need Legal Help)
• LawHelp.org: State-based directories and self-help resources. (Source: LawHelp.org—Find Help)
• American Bar Association (ABA): Information about finding free legal help and resources. (Source: ABA—Free Legal Help)

FAQs

Final Words

Learning basic legal terminology makes court papers and legal forms easier to understand. For definitions, start with official court glossaries and reputable legal references, then check your local court’s self-help site for forms and rules that apply where you live.

Disclaimer: “This is general legal information for the United States, not legal advice. Laws vary by state and facts matter.”