||An`ther*id"i*um (&?;), n.; pl. Antheridia (&?;). [Anther + &?; (a Gr. diminutive ending).] (Bot.) The male reproductive apparatus in the lower plants, consisting of a cell or other cavity in which spermatozoids are produced; -- called also spermary. -- An`ther*id"i*al (&?;), a.