[1905–10; aceto- + phenetidin]This word is first recorded in the period 1905–10. Other words that entered Englishat around the same time include: aspect ratio, cadre, one-shot, persona, thiamineaceto- is a combining form with the meanings “vinegar,” “acetic acid,” used in the formationof compound words (acetometer), esp. in the names of chemical compounds in which acetic acid or the acetyl groupis present (acetophenetidin)