Expressio unius est exclusio alterius
Expressio unius est exclusio alterius: Latin for "the expression of one thing is the exclusion of another." The canon that "expressing one item of [an] associated group or series excludes another left unmentioned" (Chevron U.S.A. Inc. v. Echazabal, 536 U.S. 73, 80 (2002)). The Court cautioned that it applies only when the items listed and the item left out naturally "go hand in hand" (at 81).
What expressio unius est exclusio alterius means
In short, expressio unius est exclusio alterius is a term you will meet in court papers, rules and legal research. The definition above gives its usual meaning in American civil practice. However, the exact meaning can depend on the rule, statute or court decision that uses it. So it helps to read the term in context.
Where expressio unius est exclusio alterius 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
Start with the primary source. For example, if expressio unius est exclusio alterius appears in a federal rule, read the rule itself and its official notes. After that, check your court’s local rules and any standing orders from the judge. In addition, search recent decisions from your own state or federal district. They show how courts read expressio unius est exclusio alterius in practice. Because state rules often differ, our state procedures guide links to each state’s official rules. Above all, make sure the version you read is still in force.
You can read the current federal court rules online for free.
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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
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