Used
来自Big Physics
Middle English: the noun from Old French us, from Latin usus, from uti ‘to use’; the verb from Old French user, based on Latin uti .
wiktionary
From Middle English used, equivalent to use + -ed.
etymonline
used (adj.)
"second-hand," 1590s, past-participle adjective from use (v.). To be used to "accustomed, familiar" is recorded by late 14c. Verbal phrase used to "formerly did or was" (as in I used to love her) represents a construction attested from c. 1300, and common from c. 1400, from use (intransitive) "be accustomed, practice customarily," but now surviving only in past tense form. The pronunciation is affected by the t- of to. Used-to-be (n.) "one who has outlived his fame" is from 1853.
