'Basidium' definitions:

Definition of 'basidium'

From: WordNet
noun
A small club-shaped structure typically bearing four basidiospores at the ends of minute projections; unique to basidiomycetes

Definition of 'Basidium'

From: GCIDE
  • Basidium \Ba*sid"i*um\, n. [NL., dim. of Gr. ba`sis base.] (Bot.) A special oblong or pyriform cell, with slender branches, which bears the spores in that division of fungi called Basidiomycetes, of which the common mushroom is an example. [1913 Webster]