a rounded aggregate of radiating crystals found in obsidian and other glassy igneous rocks.
any of several spherical masses of radiating needle-like crystals of one or more minerals occurring in rocks such as obsidian
adjective 1. having the form of a sphere; spherelike. 2. pertaining to or resembling a heavenly body; starlike. adjective (poetic) 1. resembling a sphere 2. resembling a celestial body or bodies; starlike
noun, Anatomy. 1. a circular band of voluntary or involuntary muscle that encircles an orifice of the body or one of its hollow organs. noun 1. (anatomy) a ring of muscle surrounding the opening of a hollow organ or body and contracting to close it sphincter sphinc·ter (sfĭngk’tər) n. A ringlike muscle that normally maintains […]
sphincteralgia sphinc·ter·al·gi·a (sfĭngk’tə-rāl’jē-ə, -jə) n. Pain in the muscles of the anal sphincter.
sphincterectomy sphinc·ter·ec·to·my (sfĭngk’tə-rěk’tə-mē) n. Excision of a portion of the pupillary border of the iris. Excision of a sphincter muscle.