1.(Bot.) A genus of herbs with compound white or bluish flowers; starwort; Michaelmas daisy.
2.(Floriculture) A plant of the genus Callistephus. Many varieties (called China asters, German asters, etc.) are cultivated for their handsome compound flowers.
3.(Biol.) A star-shaped figure of achromatic substance found chiefly in cells dividing by mitosis.