Definition of Polyadelphia in US English:

Polyadelphia

noun

Botany
historical
  • In the Linnaean artificial system: the eighteenth class of plants, comprising those whose flowers have numerous stamens united by their filaments into three or more bundles.

Origin

Mid 18th century; earliest use found in Chambers's Cyclopaedia. From scientific Latin Polyadelphia, former class name (Linnaeus Systema Naturae) from poly- + ancient Greek ἀδελϕός brother + scientific Latin -ia.

Pronunciation

Polyadelphia

/ˌpɒlɪəˈdɛlfɪə/