Origin of used
"second-hand," 1590s, past participle adjective from use (v.). To be used to "accustomed, familiar" is recorded by 1520s. 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, but now surviving only in past tense form. The pronunciation is affected by the t- of to.
Accustomed or habituated to. This expression is often put as be or get used to, as in I'm not used to driving a manual-shift car, or She can't get used to calling him Dad. [Early 1500s]
Formerly. This sense is used with a following verb to indicate a past state, as in I used to ride my bicycle to the post office, or This used to be the best restaurant in town. [Late 1800s]
In addition to the idiom beginning with used
- used to
- it takes getting used to
Also see underuse.