1. Rocklike deposit containing colonial marine polyps of the class Anthozoa that secrete such calcareous skeletons. Also may be of the class Hydrozoa or Bryozoa.
2.The red-orange, pinkish, or white deposits secreted by corals of the genus Corallium, used to make jewelry and ornaments. 3. The unfertilized eggs of a female lobster, which turn a reddish color when cooked. 4. The large stony corals forming coral reefs belong to various genera of Madreporaria, and to the hydroid genus, Millepora. The red coral, used in jewelry, is the stony axis of the stem of a gorgonian (Corallium rubrum) found chiefly in the Mediterranean. The fan corals, plume corals, and sea feathers are species of Gorgoniacea, in which the axis is horny. Organ-pipe coral is formed by the genus Tubipora, an Alcyonarian, and black coral is in part the axis of species of the genus Antipathes.