Definition of polysporangium in English:

polysporangium

Pronunciation /ˌpɒlɪspəˈran(d)ʒɪəm/

noun

Botany
  • A sporangium containing numerous spores, or containing polyspores, as in red algae.

Origin

Late 19th century; earliest use found in The Century Dictionary. From poly- + sporangium.