Rule of lenity
Rule of lenity: The canon that "ambiguity concerning the ambit of criminal statutes should be resolved in favor of lenity," meaning in the defendant's favor (United States v. Bass, 404 U.S. 336, 347 (1971)). It applies to unclear criminal laws, not to laws that are merely hard to read.
What rule of lenity means
Put simply, rule of lenity 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 rule of lenity 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 rule of lenity 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
- Revocable trust: a trust that the settlor can change or cancel during their lifetime.
- Right: a legally protected interest or entitlement — something the law allows a person to have or do, and that others must respect.
- Right of redemption: a right, under state law, to reclaim foreclosed property by paying the amount required within a set period.
- Right to travel: a constitutional right to move freely from state to state. The Supreme Court has recognized it in cases such as Shapiro v. Thompson, 394 U.S. 618 (1969) and Saenz v. Roe, 526 U.S. 489 (1999). Courts have consistently held that the right does not exempt a person from state driver's license and vehicle registration laws.
Why precise terms matter
Legal words often look like everyday words, but they can carry a precise meaning. Because of that, a small misreading can change how you understand a deadline, a duty or a right. Our glossary keeps each definition short and links it to the procedures where it matters.
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.