(Plural "indices" or "indexes")
1. <programming> A number used to select an element of a list, vector, array or other sequence.
Such indices are nearly always non-negative integers but see associative array.
2. <database> See inverted index.
3. <World-Wide Web> A search engine.
4. <World-Wide Web> A subject index.
4. <jargon> See coefficient of X.