Lexical Group Unique Identifier

**Semantic type:** Conceptual Entity

**Definition:** A unique identifier of a group of lexically equivalent atoms. For English language entries in the Metathesaurus, each string is linked to all of its lexical variants or minor variations by means of a common term identifier (LUI). In the Metathesaurus, therefore, an English "term" is the group of all strings that are lexical variants of each other.

**Synonyms:** - LUI - NLM LUI - UMLS LUI