/seuh ras"tee euhm/ , n. , pl. cerastiums .
any of various low-growing plants of the genus Cerastium, having leaves covered with whitish or grayish down and small white flowers, and including mouse-ear chickweed and snow-in-summer.
[ kerást ( es ) horned (see CERASTES) + NL -ium -IUM; so called from the horn-shaped seed capsules of some species ]