Efficiency
来自Big Physics
late 16th century (in the sense ‘the fact of being an efficient cause’): from Latin efficientia, from efficere ‘accomplish’ (see effect).
wiktionary
From Latin efficientia.
etymonline
efficiency (n.)
1590s, "power to accomplish something," from Latin efficientia "efficient power; efficiency; influence" (from efficientem; see efficient) + -cy. In mechanics, "ratio of useful work done to energy expended," from 1858. Attested by 1951 as short for efficiency apartment (itself from 1917).
