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.
The theca of mosses.
© Webster 1913.