||Mec`o*nid"i*um (?), n. [NL., dim. of Gr. &?; a poppy. So called in allusion to the shape of the seed capsules of the poppy.] (Zoöl.) A kind of gonophore produced by hydroids of the genus Gonothyræa. It has tentacles, and otherwise resembles a free medusa, but remains attached by a pedicel.