plagueyoudaoicibaDictYouDict[plague 词源字典]
plague: [14] Etymologically, plague means a ‘blow’ or ‘stroke’. It goes back to the same prehistoric base, *plag- ‘hit’, as produced Latin plangere ‘beat’ (source of English complain, plaintiff [14], plaintive [14], and plangent [19] – which originally denoted the sound of waves ‘beating’ against the shore) and English plankton.

From this was derived Greek plāgá ‘blow’, which was borrowed into Latin as plāga ‘blow’, hence ‘wound’. In the Vulgate it was used for an ‘infectious disease’, and was borrowed in this sense (as well as the now defunct ‘blow’) via Old French into English. (*Plak-, a parallel form to *plag-, lies behind English apoplexy and plectrum [17].)

=> apoplexy, complain, plaintive, plangent, plankton, plectrum[plague etymology, plague origin, 英语词源]
plague (n.)youdaoicibaDictYouDict
late 14c., plage, "affliction, calamity, evil, scourge;" early 15c., "malignant disease," from Old French plage (14c.), from Late Latin plaga, used in Vulgate for "pestilence," from Latin plaga "stroke, wound," probably from root of plangere "to strike, lament (by beating the breast)," from or cognate with Greek (Doric) plaga "blow," from PIE *plak- (2) "to strike, to hit" (cognates: Greek plazein "to drive away," plessein "to beat, strike;" Old English flocan "to strike, beat;" Gothic flokan "to bewail;" German fluchen, Old Frisian floka "to curse").

The Latin word also is the source of Old Irish plag (genitive plaige) "plague, pestilence," German Plage, Dutch plaage. Meaning "epidemic that causes many deaths" is from 1540s; specifically in reference to bubonic plague from c. 1600. Modern spelling follows French, which had plague from 15c. Weakened sense of "anything annoying" is from c. 1600.
plague (v.)youdaoicibaDictYouDict
late 15c., from Middle Dutch plaghen, from plaghe (n.) "plague" (see plague (n.)). Sense of "bother, annoy" it is first recorded 1590s. Related: Plagued; plaguing.