ETYM Latin infinitus: cf. French infini. Related to In- not, and Finite.
1. Total and all-embracing.
2. Having no limits or boundaries in time or space or extent or magnitude.
3. (Grammar) Of verbs; having neither person nor number nor mood (as a participle or gerund or infinitive); SYN. non-finite.

Something that is infinite (as in extent, duration, or number)