coral |ˈkôrəl; ˈkär-| noun 1 a hard stony substance secreted by certain marine coelenterates as an external skeleton, typically forming large reefs in warm seas : [as adj. ] a coral reef. • precious red coral, used in jewelry. • the pinkish-red color of red coral. 2 a sedentary coelenterate of warm and tropical seas, with a calcareous, horny, or soft skeleton. Most corals are colonial and many rely on the presence of green algae in their tissues to obtain energy from sunlight. • Several orders in the class Anthozoa, including the ‘true’ or stony corals (order Scleractinia or Madreporaria), which form reefs, the soft corals (order Alcyonacea), and the horny corals (order Gorgonacea). 3 the unfertilized roe of a lobster or scallop, which is used as food and becomes reddish when cooked. DERIVATIVES coralloid |-ˌloid| adjective ( chiefly Biology Zoology). ORIGIN Middle English : via Old French from Latin corallum, from Greek korallion, kouralion.