英语词源字典 - 在线词源网站

aback (adv.)[aback 词源字典]: c. 1200, from Old English on bæc "at or on the back;" see back (n.). Now surviving mainly in taken aback, originally a nautical expression in reference to a vessel's square sails when a sudden change of wind flattens them back against the masts and stops the forward motion of the ship (1754). The figurative sense is first recorded 1840.[aback etymology, aback origin, 英语词源]
caprice (n.): "sudden change of mind," 1660s, from French caprice "whim" (16c.), from Italian capriccio "whim," originally "a shivering," possibly from capro "goat," with reference to frisking, from Latin capreolus "wild goat" (see cab). But another theory connects the Italian word with capo "head" + riccio "curl, frizzled," literally "hedgehog" (from Latin ericius). The notion in this case would be of the hair standing on end in horror, hence the person shivering in fear.
peripeteia (n.): also peripetia, 1590s, from Greek peripeteia "a turn right about; a sudden change" (of fortune, in a tragedy), from peri- "around" (see peri-) + stem of piptein "to fall" (see symptom).