1580s, "offering one or the other of two," from Medieval Latin alternativus, from Latin alternatus, past participle of alternare (see alternate, v.). Meaning "purporting to be a superior choice to what is in general use" was current by 1970 (earliest reference is to the media). Alternative energy is from 1975. Related: Alternatively.

1620s, in rhetoric, from Medieval Latin alternativus (see alternative, adj.). Of courses of action, from 1814. Of objects, etc., "the other of two which may be chosen," by 1838.