ˈastə(r), ˈaas- noun
Etymology: in senses 1 and 2, from New Latin, from Latin, aster, from Greek aster-, astēr star, aster; in sense 3, from New Latin, from Late Latin, star, from Greek aster-, astēr; in sense 4, from Middle Greek aster-, astēr, from Greek, star — more at star
1. capitalized : a large genus of chiefly fall-blooming leafy-stemmed herbaceous plants (family Compositae) native of temperate regions and having discoid and usually daisylike radiate heads, a multiseriate involucre, and a pappus of a single series of capillary bristles — see michaelmas daisy
2. -s
a. : any plant of the genus Aster or its immediate related forms
b. : any of a number of plants derived from the China aster
3. -s biology : a system of gelated cytoplasmic rays (aster rays) typically arranged radially about a centrosome at either end of the mitotic spindle and sometimes persisting between mitoses — called also cytaster
4. Eastern Church : asterisk 2