Oophoridium \O`o*pho*rid"i*um\, n.; pl. L. {Oophorida}, E. {Oophoridiums}. [NL., dim. fr. Gr. ?. See {Oophore}.] (Bot.) The macrosporangium or case for the larger kind of spores in heterosporous flowerless plants. [1913 Webster]