Tern \Tern\, a. [L. pl. terni three each, three; akin to tres three. See {Three}, and cf. {Trine}.] Threefold; triple; consisting of three; ternate. [1913 Webster] {Tern flowers} (Bot.), flowers growing three and three together. {Tern leaves} (Bot.), leaves arranged in threes, or three by three, or having three in each whorl or set. {Tern peduncles} (Bot.), three peduncles growing together from the same axis. {Tern schooner} (Naut.), a three-masted schooner. [1913 Webster]