iure

iure is a Latin term meaning by law or legally. It is the ablative singular of ius, the word for law or right, and it is used in legal and scholarly Latin to indicate the basis, source, or manner by which something is justified or authorized.

In grammar, iure derives from ius (genitive iuris) and appears in phrases where the ablative expresses means, cause, or accompaniment. As an adverbial expression, iure often functions to designate that a statement, action, or entitlement rests on law or legal right. Because it is a Latin token, it is most commonly encountered in legal, canon, or philosophical writings rather than in ordinary English prose.

Historically, iure appears in medieval and early modern legal contexts and in treatises on natural law, civil law, or canon law. It forms part of expressions such as iure divino (by divine law) or iure humano (by human law), as well as discussions of ius gentium (the law of nations) or ius civile (civil law). These usages illustrate how Latin legal language categorized authority, legitimacy, and procedural grounding.

In modern English-language scholarship, iure is usually encountered only in Latin quotes or phrases. Its everyday English equivalents are "by law" or "legally." For most purposes, ius or iuris is used to refer to law or rights, while iure remains a specialized Latin term primarily of historical or philological interest.

See also: ius, iuris, ius civile, ius naturale, ius gentium, jurisconsultus.