Definition of megasporangium in US English:

megasporangium

noun

Botany
  • A sporangium containing megaspores; the part of a plant in which the female gametophyte is formed.

Origin

Late 19th century; earliest use found in The Athenaeum. From mega- + sporangium, after megaspore.

Pronunciation

megasporangium

/ˌmɛɡəspəˈran(d)ʒɪəm/