英语词源字典 - 在线词源网站

AC [AC 词源字典]: abbreviation of air conditioning, by 1966.[AC etymology, AC origin, 英语词源]
air conditioner (n.): from air (n.1) + agent noun from condition; along with air-conditioning, first attested 1909, originally an industrial process; main modern use in residences and office buildings is from 1930s.
condition (v.): late 15c., "to make conditions," from condition (n.). Meaning "to bring to a desired condition" is from 1844. Related: Conditioned; conditioning.
operant (adj.): "that works," early 15c., from Latin operantem (nominative operans), present participle of operari "to work" (see operation). Psychological sense of "involving behavior modification" coined 1937 by U.S. psychologist B.F. Skinner (as in operant conditioning, 1938, Skinner).
recondition (v.): also re-condition, 1850, from re- "back, again" + condition (v.). Related: Reconditioned; reconditioning.
verbal (adj.): early 15c., "dealing with words" (especially in contrast to things or realities), from Old French verbal (14c.) and directly from Late Latin verbalis "consisting of words, relating to verbs," from Latin verbum "word" (see verb). Related: Verbally. Verbal conditioning is recorded from 1954. Colloquial verbal diarrhea is recorded from 1823. A verbal noun is a noun derived from a verb and sharing in its senses and constructions.