Corallite (kawr’–uh-lahyt) The calcium carbonate exo-skeleton of a coral polyp.
Polyp (pol’-ip) With regard to coral reefs, a tiny, colonial, sac-like animal fixed to a substrate and protected by a calcium carbonate external skeleton.
Zooxanthellae (zoh-uh-zan-thel’-ee) Symbiotic dinoflagellate algae embedded in the tissues of coral polyps that perform photosynthesis to produce nutrients shared with the host polyps. A major factor in the growth of reef-building corals.