dictionary (n.)youdaoicibaDictYouDict
1520s, from Medieval Latin dictionarium "collection of words and phrases," from Latin dictionarius "of words," from dictio "word" (see diction). Probably first English use in title of a book was in Sir Thomas Elyot's "Latin Dictionary" (1538) though Latin Dictionarius was so used from early 13c. Grose's 1788 "Dictionary of the Vulgar Tongue" has "RICHARD SNARY. A dictionary."
DICTIONARY, n. A malevolent literary device for cramping the growth of a language and making it hard and inelastic. This dictionary, however, is a most useful work. [Bierce]
efficiency (n.)youdaoicibaDictYouDict
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).