Why is the ninth month called September?
"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.