How does a thesaurus differ from a taxonomy?
A thesaurus is an arrangement of terms (words or phrases), with a simple hierarchy of parent-child relationships described as broader terms (BT) and narrower terms (NT). But thesauri also introduce the concept of synonym relationships, a set of equivalent terms that may be substituted for one another, usually with one preferred term (PT). In addition, thesauri allow arbitrary associative relationships between terms. References to a term such as See and See also are examples of related terms (RT).
