||Pyx*id"i*um (?), n.; pl. Pyxidia (#). [NL., fr. Gr. &?;, dim. a &?; a box. See Pyx.] (Bot.) (a) A pod which divides circularly into an upper and lower half, of which the former acts as a kind of lid, as in the pimpernel and purslane. (b) The theca of mosses.