- [Bot] A genus of herbs with compound white or bluish flowers; starwort; Michaelmas daisy.
- [Floriculture] A plant of the genus Callistephus. Many varieties (called China asters German asters, etc.) are cultivated for their handsome compound flowers.
- [Biol] A star-shaped figure of achromatic substance found chiefly in cells dividing by mitosis.
Etymology: L. aster aster, star, Gr. 'asth`r star. See Star