Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Unified Medical Language System® (UMLS®)

Lexical Entries

There is one lexical entry for each spelling or set of spelling variants in a particular part of speech. Each lexical record contains information on:

  • Base form of the term
  • The part of speech
  • A unique identifier
  • Rules for spelling variants

The base form of a term is the uninflected form of the item; the singular form in the case of a noun, the infinitive form in the case of a verb, and the positive form in the case of an adjective or adverb.

The lexicon recognizes eleven parts of speech:
Verbs
Nouns
Adjectives
Adverbs
Auxiliaries
Modals
Pronouns
Prepositions
Conjunctions
Complementizers
Determiners

Approximately eighty-six percent of the entries are nouns.

 

Last Reviewed: July 29, 2016