- The achromatic figure, created in mitotic mobile division, composed of two asters linked by a spindle-shaped bundle of rod-like fibres diverging from each aster.
- The achromatic figure, formed in mitotic cell-division, composed of two asters linked by a spindle-shaped bundle of rodlike fibers diverging from each aster, and labeled as the spindle.
- A genus of starfishes, associated with household Goniasteridæ.
- [lowercase] In embryology, a formation in a maturing ovum of a fusiform figure radiated at either end, thus resembling two stars joined collectively, whence title. See plant.
- [lowercase] A sponge-spicule consisting of a straight axis with a whorl of rays near each end.