mid-14c., prompten, from Latin promptus, past participle of promere "to bring forth," from pro- "forward" (see pro-) + emere "to take" (see exempt (adj.)). Theatrical sense of "to assist a speaker with lines" is first recorded early 15c. Related: Prompted; prompting.
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.