| Annulus 1. (n.) A ring; a ringlike part or space. 2. (n.) A space contained between the circumferences of two circles, one within the other. 3. (n.) The solid formed by a circle revolving around a line which is the plane of the circle but does not cut it. 4. (n.) Ring-shaped structures or markings, found in, or upon, various animals. Thesaurus Entries O, annular muscle, annulus, aureole, chaplet, circle, circuit, circumference, circus, closed circle, corona, coronet, crown, cycle, diadem, discus, disk, eternal return, fairy ring, garland, glory, halo, lasso, logical circle, loop, looplet, magic circle, noose, orbit, radius, ring, rondelle, round, roundel, saucer, sphincter, vicious circle, wheel, wreath |