In theory, any significant word, phrase or number which forms part of a catalogue can be indexed. A word or phrase which can usefully be indexed is known as a keyword. To prepare an index, all keywords of a particular type are arranged in an appropriate sequence. They are cross-referenced to the catalogue, via the identity number. Retrieval is the recall of information, usually via an index or computerised search.
Indexing increases the accessibility of a museum collection.
Normally there will be a core of two or three particularly useful indexes which are set up when the documentation system is created. If an additional index is needed, this can be set up whenever there is someone available to do the work. If the structure, syntax and vocabulary of the catalogue records is correct, then indexing becomes routine. What indexes you need will depend on the type of collection, the uses to which it is put and the kind of enquiries you receive. Computerised databases can be indexed more easily.