queue: [16] Etymologically a queue is simply a ‘tail’. That was the meaning of its Latin ancestor cauda, a word of unknown origin which has also given English caudal ‘of a tail’ [17] and, via Italian, coda [18] (literally a ‘tail’-piece). To begin with in English queue (acquired via French) was used only as a technical term in heraldry for a ‘tail’. It was not until the 18th century that metaphorical applications started to appear: to a ‘billiard stick’ (now spelled cue) and a ‘pigtail’. ‘Line of people waiting’ (which has never caught on in American English) emerged in the early 19th century. => coda[queue etymology, queue origin, 英语词源]