Entry 1 sense Webster, 1913 Polyanthus /(pŏl`ĭ*ăn"thŭs)/ · Pol·y·an·thus · IPA 01 n. The oxlip. So called because the peduncle bears a many-flowered umbel. See Oxlip. pl. Polyanthuses ((#)) 1. The oxlip. So called because the peduncle bears a many-flowered umbel. See Oxlip.(Bot.) See: Oxlip