prompt (n.)
early 15c., "readiness," from Latin promptus (see prompt (v.)). Meaning "hint, act of prompting" is from 1590s. Computer sense attested by 1977.
prompt (adj.)
early 15c., from Old French prompt and directly from Latin promptus "brought forth," hence "visible, apparent, evident," past participle of promere "to take or bring out or forth" (see prompt (v.)).Related: Promptly; promptitude.
prompt (v.)
mid-14c., prompten, from Latin promptus, past participle of promere "to bring forth," from pro "forward" (from PIE root *per- (1) "forward") + emere "to take" (see exempt (adj.)). Theatrical sense of "to assist a speaker with lines" is first recorded early 15c. Related: Prompted; prompting.