Oath
Oath: A solemn declaration, usually invoking a sense of moral or religious obligation, that a statement is true or that a person will faithfully perform a duty. Before testifying, a witness must give an oath or affirmation to testify truthfully (Fed. R. Evid. 603). An affirmation is a solemn promise without a religious reference, and the law treats it the same as an oath. In most federal matters, a signed, dated declaration under penalty of perjury may substitute for a sworn statement, though not for depositions or oaths of office (28 U.S.C. § 1746).
What oath means
Put simply, oath is part of the working vocabulary of a civil case. The short definition above covers the usual meaning. Still, a specific rule, statute or contract can give it a narrower meaning. For that reason, check how it is used in your own documents.
Where oath comes up
The term is used across many kinds of cases. For example, you may see it in pleadings, motions and court orders. To see it in context, browse the motions and procedures library or the Learn the Law topics.
How to research the term
First, read the term where it actually appears. A rule, statute or court decision may define it for its own purposes. Next, check whether your court has a local rule that uses oath in a special way. Then look at recent decisions from courts in your jurisdiction. They show how judges apply the term today. Also, remember that state law can differ from federal law. For that reason, use our state procedures guide to find your state’s rules. Finally, confirm every source is current before you rely on it.
You can read the current federal court rules online for free.
Related legal terms
- Notary: a notary public, a public officer commissioned by a state to witness signatures, confirm the identity of signers, take acknowledgments and administer oaths.
- Notice: information about a fact, a claim or a proceeding.
- Notice of appeal: the document that starts an appeal.
- Nunc pro tunc: latin for "now for then." A court order that takes effect as of an earlier date, often to correct the record so it reflects what actually happened.
Why precise terms matter
Courts read legal terms closely. As a result, knowing the exact meaning of a word helps you follow orders, rules and filings. Each glossary entry on Lawtopolis is short on purpose and links to the pages where the term is used.
Sources
Sources last reviewed: 2026-10-24
Lawtopolis provides legal information and education, not legal advice. Using this site does not create an attorney-client relationship. Laws and court rules vary by jurisdiction and change over time; verify every authority against the official source and consult a licensed attorney in your jurisdiction about your situation.