Definition of progymnosperm in US English:

progymnosperm

noun

Botany
  • Originally: a primitive or ancestral gymnosperm. Now: specifically any of a group of sporogenous fossil plants having secondary wood resembling that of gymnosperms.

Origin

Late 19th century; earliest use found in Nature: a weekly journal of science. From pro- + gymnosperm, probably after French progymnosperme.

Pronunciation

progymnosperm

/prəʊˈdʒɪmnə(ʊ)spəːm/