Originally: †a stalked antheridium of a moss, liverwort, or other cryptogam (obsolete rare). In later use: a spore produced at the apex of a hypha or other cellular filament forming the structural element of a fungus; a basidiospore.
((n.) A spore borne at the extremity of the cells of
fructification in fungi.)
Origin:
Mid 19th century; earliest use found in William Henry Harvey (1811–1866), botanist. From acro- + spore, probably after French acrospore. Compare German Akrospore.