1. Any of various plants of the genus Aster or closely related genera in the composite family, having radiate flower heads with white, pink, or violet rays and usually a yellow disk.
2. The China aster.
3. Biology A star-shaped structure formed in the cytoplasm of an animal cell during mitosis, having raylike microtubules that surround the centrosome.
[Latin astēr, a type of plant, from Greek, star, type of daisy; see ster-3 in the Appendix of Indo-European roots.]
(click for a larger image)aster
European Michaelmas daisies
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