agoyoudaoicibaDictYouDict[ago 词源字典]
ago: [14] Historically, ago is the past participle of a verb. Its earlier, Middle English, form – agone – reveals its origins more clearly. It comes from the Old English verb āgān ‘pass away’, which was formed from gān ‘go’ and the prefix ā- ‘away, out’. At first it was used before expressions of time (‘For it was ago five year that he was last there’, Guy of Warwick 1314), but this was soon superseded by the now current postnominal use.
=> go[ago etymology, ago origin, 英语词源]
die (v.)youdaoicibaDictYouDict
mid-12c., possibly from Old Danish døja or Old Norse deyja "to die, pass away," both from Proto-Germanic *dawjan (cognates: Old Frisian deja "to kill," Old Saxon doian, Old High German touwen, Gothic diwans "mortal"), from PIE root *dheu- (3) "to pass away, die, become senseless" (cognates: Old Irish dith "end, death," Old Church Slavonic daviti, Russian davit' "to choke, suffer").

It has been speculated that Old English had *diegan, from the same source, but it is not in any of the surviving texts and the preferred words were steorfan (see starve), sweltan (see swelter), wesan dead, also forðgan and other euphemisms.

Languages usually don't borrow words from abroad for central life experiences, but "die" words are an exception, because they are often hidden or changed euphemistically out of superstitious dread. A Dutch euphemism translates as "to give the pipe to Maarten." Regularly spelled dege through 15c., and still pronounced "dee" by some in Lancashire and Scotland. Used figuratively (of sounds, etc.) from 1580s. Related: Died; dies.
evanesce (v.)youdaoicibaDictYouDict
"vanish by degrees, melt into thin air," 1817, a back-formation from evanescence, or else from Latin evanescere "to pass away, vanish" (see evanescent).
evanescent (adj.)youdaoicibaDictYouDict
1717, "on the point of becoming imperceptible," from French évanescent, from Latin evanescentem (nominative evanescens), present participle of evanescere "disappear, vanish, pass away," figuratively "be forgotten, be wasted," from assimilated form of ex- "out" (see ex-) + vanescere "vanish" (see vanish). Sense of "quickly vanishing, having no permanence" is by 1738.
transient (adj.)youdaoicibaDictYouDict
c. 1600, "transitory, not durable," from Latin transientem (nominative transiens) "passing over or away," present participle of transire "cross over, go over, pass over, hasten over, pass away," from trans- "across" (see trans-) + ire "to go" (see ion). Meaning "passing through a place without staying" is from 1680s. The noun is first attested 1650s; specific sense of "transient guest or boarder" attested from 1857. Related: Transiently.
vanish (v.)youdaoicibaDictYouDict
"disappear quickly," c. 1300, from shortened form of esvaniss-, stem of Old French esvanir "disappear; cause to disappear," from Vulgar Latin *exvanire, from Latin evanescere "disappear, pass away, die out," from ex- "out" (see ex-) + vanescere "vanish," inchoative verb from vanus "empty" (see vain). Related: Vanished; vanishing; vanishingly. Vanishing point in perspective drawing is recorded from 1797.