Reef (rēf), n. [Akin to D. rif, G. riff, Icel. rif, Dan. rev; cf. Icel. rifa rift, rent, fissure, rifa to rive, bear. Cf. Rift, Rive.] 1. A chain or range of rocks lying at or near the surface of the water. See Coral reefs, under Coral.
2. (Mining.) A large vein of auriferous quartz; — so called in Australia. Hence, any body of rock yielding valuable ore.
Reef builder(Zoöl.), any stony coral which contributes material to the formation of coral reefs. — Reef heron(Zoöl.), any heron of the genus Demigretta; as, the blue reef heron (D. jugularis) of Australia.