- asterAny of several plants of the genus Aster; one of its flowers.
- aster-Relating to stars.
- asterionThe point on the side of the skull corresponding to the posterior end of the parietomastoid suture.
- asterophylliteA fossil plant from the coal formations of Europe and America, now regarded as the branchlets and foliage of calamites.
- asteroseismologyThe study of oscillations in stars.
- astraeanRelating to the former genus Astraea or the family Astraeidae.
- astrophylliteA rare, brown to golden-yellow hydrous potassium iron titanium silicate mineral, visually identical to kupletskite.
- diasterA double star; applied to the nucleus of a cell, when, during cell division, the loops of the nuclear network separate into two groups, preparatory to the formation of two daughter nuclei.