Word Origin & History
c.1500, from L. arbiter "one who goes somewhere (as witness or judge)," from ad- "to" + baetere "to come, go." The spec. sense of "one chosen by two disputing parties to decide the matter" is from 1540s. The earliest form of the word attested in English is the fem. noun arbitress (mid-14c.) "a woman
who settles disputes."