fluxyoudaoicibaDictYouDict[flux 词源字典]
flux: [14] Flux denotes generally ‘flowing’, and comes from Latin fluxus, a derivative of the past participle of fluere ‘flow’. This verb, similar in form and meaning to English flow but in fact unrelated to it, is responsible for a very wide range of English words: its past participle has given us fluctuate [17], its present participle fluent [16] and a spectrum of derived forms, such as affluent, effluent [18], and influence, and other descendants include fluid [15] (literally ‘flowing’, from Latin fluidus), mellifluous (literally ‘flowing with honey’), superfluous [15], and fluvial [14] (from Latin fluvius ‘river’, a derivative of fluere).

Latin fluxus also produced the card-playing term flush [16].
=> affluent, effluent, fluctuate, fluent, fluid, influence, mellifluous, superfluous[flux etymology, flux origin, 英语词源]
flux (n.)youdaoicibaDictYouDict
late 14c., "abnormally copious flow," from Old French flus "a flowing, a rolling; a bleeding" (Modern French flux), or directly from Latin fluxus (adj.) "flowing, loose, slack," past participle of fluere "to flow" (see fluent). Originally "excessive flow" (of blood or excrement), it also was an early name for "dysentery;" sense of "continuous succession of changes" is first recorded 1620s. The verb is early 15c., from the noun.