VIII. Definition of a Descriptor or Main Term

It is crucial for all participants to be familiar with each other's scope note or definition of a preferred term or descriptor. If there are pre-existing discrepancies in how the participants define the concept of a descriptor, a clear understanding of the differences should be reached as work begins.

For example, AAT descriptors represent single concepts, do not as a rule contain punctuation, and are never in inverted form. They represent the conventional usage of the term in the field and the most widely accepted spelling in American English. Most descriptors are nouns (building) or noun phrases (historic building). Freestanding adjectives are included as descriptors in some hierarchies so that they can be used as modifiers of other descriptors (octagonal). Their inclusion serves to avoid undue enumeration of phrases composed of adjectives plus nouns (circular room, circular barn, etc. ). Gerund forms are also included in the hierarchies in the Activities facet (repairing). Prepositional phrases and phrases containing conjunctives are generally excluded from the thesaurus, except when they express single concepts (wattle and daub)[16]. In order to accommodate the different term forms found in other thesauri, sometimes two AAT terms will be accepted as a postcoordinated equivalent to a single descriptor in another language (e. g. , perfume + factories = parfumerie).

16. Guide to Indexing and Cataloging with the Art & Architecture Thesaurus, Chapter 1, paragraph 4. 3, and Appendix C.