• scope noteA note following a term explaining its coverage, specialized usage, or rules for assigning it.
  • semantic linkingA method of linking terms according to their meaning or meanings.
  • semantic webA representation in two (or possibly three) dimensions of the semantic relationships between and among terms and the concepts they represent.
  • siblingA term that shares the same broader term (one level higher) as other terms.
  • stop listA list of words considered to be of no value for retrieval. It consists primarily of function words “articles, conjunctions, and prepositions” but may also include words that occur very frequently in the literature of a domain.
  • subheadingA term appended to a heading in order to modify or delimit the heading by indicating a particular aspect or relationship pertaining to it. A term with a subheading may be subject to further modification. See also precoordination.
  • subject headingA word or phrase, or any combination of words, phrases, and modifiers used to describe the topic of a content object. Precoordination of terms for multiple and related concepts is a characteristic of subject headings that distinguishes them from controlled vocabulary terms. See also ...
  • subject heading listAn alphabetical list of subject headings with cross-references from non-preferred terms and links to related terms. These lists often include separate sequences of standardized subheadings that may be combined with all or only some subject headings. Rules for applying subheadings usually ...
  • symmetricHaving symmetry. In the context of controlled vocabularies reciprocal relationships are symmetric when the relationship indicator used between a pair of linked terms is the same in one direction as it is in the reverse direction, e.g. RT / RT. See also asymmetric and reciprocity.
  • synonymA word or term having exactly or very nearly the same meaning as another word or term.
  • synonym ringA group of terms that are considered equivalent for the purposes of retrieval.