noun

• (Australia, South Africa) A large vein of auriferous quartz; hence, any body of rock yielding valuable ore.

noun

• (nautical) 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."

verb

• (nautical) To take in part of a sail in order to adapt the size of the sail to the force of the wind.
  ""When the day arrived that the boy was to be skipper, the weather was calm and fine, but he called all men to reef sails, so the ship had scarcely any sail on her.""
• (Australia) To pull or yank strongly, especially in relation to horse riding.
  "And when the Cup came on he stirred them up ′round the barrier and he flew out of the barrier and he pulled and reefed and pulled and reefed and Lewis didn′t let him settle down until about three furlongs from home and when he did settle the horse was all out of stride and he went back through the field a fair bit."
• (nautical, of paddles) To move the floats of a paddle wheel toward its center so that they will not dip so deeply.
  "Reef the paddles."
• (slang) To manipulate the lining of a person's pocket in order to steal the contents unnoticed.
  "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, as he might have taken out anything else."

noun

• (Now chiefly dialectal) The itch; any eruptive skin disorder.
• (Now chiefly dialectal) Dandruff.