reef

A chain or range of rocks, sand, or coral lying at or near the surface of the water.

A large vein of auriferous quartz; hence, any body of rock yielding valuable ore.AustraliaSouth-Africa

A portion of a sail rolled and tied down to lessen the area exposed in a high wind.

• They sailed as if they were stark mad; they never took in a reef in the sail, and when the seas filled the boat, they sailed her up on the back of a wave till she stood nearly on end, the water rushing out over her stern as out of a spout.

A reef knot.

To take in part of a sail in order to adapt the size of the sail to the force of the wind.

• 1970 July–December, Margaret Quilty, Roller Reefing Made Easy, Boating, page 63, Be sure the blocks are securely mounted—they carry a fairish load when the sail is reefed. If both reefing line and main halyard are led to the cockpit, even s

To pull or yank strongly, especially in relation to horse riding.Australia

• He reefed on the handbrake and sat smoking his cigarette, gazing out through the windscreen at the driveway.

To move the floats of a paddle wheel toward its center so that they will not dip so deeply.

• Reef the paddles.

To manipulate the lining of a person's pocket in order to steal the contents unnoticed.slang

• This was done by "reefing." He put two fingers just inside the opening and lifted the lining a trifle. Although I watched his hands, I could feel nothing, so gently did his fingers work. Reefing a couple of times, he lifted my handkerchief,

Scabby; scurvy.

The itch; any eruptive skin disorder.

Dandruff.