An indicator that the associated term (or other designation) is the primary designation for the concept described in the entry. If there is only one designation in the entry, it is automatically the preferred term and there is no need to mark it as such by using this element. It is recommended that the preferred term fulfills the criteria described in Clause 6.2.1 of ISO 10241-1 - Terminological entries in standards -- Part 1: General requirements and examples of presentation. If the selection of more than one preferred term is unavoidable, enter the preferred terms in the order of preference. Ideally, among all the terms in an entry, only the preferred term should be used in the body of the standard.

An admitted term (or designation) is synonymous with the preferred term, but is considered by the standardizing committee to be a less desirable term than the preferred term. An admitted term is an acceptable term that has no negative connotations or other negative properties that would qualify it as a deprecated term. Admitted terms are often commonly-used synonyms of standardized (preferred) terms. If there are several admitted terms, include them in the entry in the order of preference. Admitted terms can occur in the body of the standard, but the preferred term should be used more frequently.

A deprecated term (or designation) is synonymous with the preferred term, but is rated as undesired by the standards committee. Deprecated terms include obsolete terms, superseded terms, archaic terms, scientific-technical slang, ambiguous terms, terms with negative connotations, terms which are culturally-specific or used by a restricted user group within the target community, and any term that does not facilitate effective, clear communication. Deprecated terms and designations should not be used in the body of the standard.