Definition of coral reef

The term "coral reef" is a combination of two words: "coral" and "reef". "Coral" comes from the Latin word "coralium", which itself likely derives from the Greek word "koraillon", referring to a type of red seaweed. "Reef" originates from the Old English word "rīf", meaning "ridge" or "row". The combination of these two words, "coral reef", accurately describes the underwater ridge or row of rock-like formations built by tiny marine animals called coral polyps.