The Collaborative International Dictionary
Polyadelphia
Polyadelphia \Pol`y*a*del"phi*a\, n. pl. [NL., fr. Gr. poly`s many + ? brother.] (Bot.) A Linn[ae]an class of plants having stamens united in three or more bodies or bundles by the filaments.
Wiktionary
polyadelphia
n. (context obsolete English) A former taxonomic class of plants having the stamens united by their filaments into bundles