(anatomy) A primitive alimentary cavity

A specimen of the species Archaeopteryx lithographica, being the earliest and most primitive known bird, representing a transition in the evolution of dinosaurs to birds.

plural of archenteron

plural of archenteron

(anatomy) Of or pertaining to an archenteron.

plural of archegonium

(botany) A multicellular reproductive structure that contains a large, non-motile gamete (egg cell), and within which an embryo will develop.

Alternative spelling of archaebacterium

(botany) Relating to the archegonium.

(biology) The origination of living matter from non-living; abiogenesis.