- efficiency (n.)
[efficiency 词源字典]
- 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 from 1952 as short for efficiency apartment (itself from 1920).[efficiency etymology, efficiency origin, 英语词源]