Entry 1 sense Webster, 1913 Gymnoplast /(jĭm"nō̇*plăst)/ · Gym·no·plast · IPA 01 n. A cell or mass of protoplasm devoid of an envelope, as a white blood corpuscle. 1. A cell or mass of protoplasm devoid of an envelope, as a white blood corpuscle.(Biol.)