REEF

A chain or range of rocks lying at or near the surface of the water. See Coral reefs, under Coral.

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.

That part of a sail which is taken in or let out by means of the reef points, in order to adapt the size of the sail to the force of the wind.

To reduce the extent of (as a sail) by roiling or folding a certain portion of it and making it fast to the yard or spar. Totten. To reef the paddles, to move the floats of a paddle wheel toward its center so that they will not dip so deeply.