Thesauri semantics

hierarchical relations Thesauri are hierarchies with broader/narrower relations structuring the hierarchy.

associative relations UF, USE and RT. UF is a synonym term with its reciprocal USE, which are used to show that one and only one of a set of terms with equivalent meaning is preferred by the categorisation system and is used for indexing.

All thesauri		Multilingual thesauri
Top Term	TT	Exact Equivalent
Broader Term	BT	Inexact Equivalent
Narrower Term	NT	Partial Equivalent
Related Term	RT	One to Many Equivalent
Used For	UF	Language of
Use
Scope Note

Many thesauri introduce other relations when useful; e.g. DEF (definition) in the NASA thesaurus.

The multilingual relations map two languages as illustrated in the table below (from Aitchison, Gilchrist, Bawden, 1997 - it is the definitive work on constructing thesauri):