atrium in French

(architecture) A central room or space in ancient Roman homes, open to the sky in the middle; a similar space in other buildings.

(palynology) A cavity inside a porate aperture of a pollen grain formed by the separation of the sexine and nexine layers, widening toward the interior of the grain.

(palynology) A cavity inside a porate aperture of a pollen grain formed by the separation of the sexine and nexine layers, widening toward the interior of the grain.