‖n.; pl. Cnidæ [ NL., fr. Gr. kni`dh nettle, sea nettle. ] (Zool.) One of the peculiar stinging cells found in Cœlenterata; a nematocyst; a lasso cell. [ 1913 Webster ]

‖n. pl. [ NL. See Cnida. ] (Zool.) A comprehensive group equivalent to the true Cœlenterata, i. e., exclusive of the sponges. They are so named from presence of stinging cells (cnidae) in the tissues. See Coelenterata. [ 1913 Webster ]