reef

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A strip or ridge of rocks, sand, or coral that rises to or near the surface of a body of water.
2. n. A vein of ore.
3. n. A portion of a sail rolled and tied down to lessen the area exposed to the wind.
4. v. To reduce the size of (a sail) by tucking in a part and tying it to or rolling it around a yard.
5. v. To shorten (a topmast or bowsprit) by taking part of it in.

Century Dictionary and Cyclopedia

1. n. A low, narrow ridge of rocks, rising ordinarily but a few feet above the water. A reef passes by increase of size into an island. The word is especially used with reference to those low islands which are formed of coralline debris. See atoll, and coral reef, below.
2. n. Any extensive elevation of the bottom of the sea; a shoal; abank: so called by fishermen.
3. n. In Australia, the same as lode, vein, or ledge of the Cordilleran miner: as, a quartz-reef (that is, a quartz-vein).
4. n. A kind of commercial sponge which grows on reefs.
5. n. Nautical, a part of a sail rolled or folded up, in order to diminish the extent of canvas exposed to the wind. In topsails and courses, and sometimes in top-gallantsails, the reef is the part of the sail between the head and the first reef-band, or between any two reef-bands; in fore-and-aft sails reefs are taken on the foot. There are generally three or four reefs in topsails, and one or two in courses.
6. Nautical, to take a reef or reefs in; reduce the size of (a sail) by rolling or folding up a part and securing it by tying reef-points about it. In square sails the reef-points are tied round the yard as well as the sail; in fore-and-aft sails they may or may not be tied round the boom Which extends the foot of the sail. In very large ships, where the yards are so large as to make it inconvenient to tie the reef-points around them, the sails are sometimes reefed to jackstays on the yards.
7. To gather up stuff of any kind in away similar to that described in def. 1. Compare reefing.
8. See the quotation.
9. Scabby; scurvy.
10. n. The itch; also, any eruptive disorder.
11. n. Dandruff.
12. n. In the Tyrolese Alps, and especially in the region of the dolomites, “massive un-stratified limestones and dolomites rising amid strikingly contrasted sediments.”
13. In Australian mining, to work at a reef.

Wiktionary

1. adj. Scabby; scurvy.
2. n. The itch; any eruptive skin disorder.
3. n. Dandruff.
4. n. A chain or range of rocks, sand, or coral lying at or near the surface of the water.
5. n. Australia, South Africa A large vein of auriferous quartz; hence, any body of rock yielding valuable ore.
6. n. nautical A portion of a sail rolled and tied down to lessen the area exposed in a high wind.
7. n. A reef knot.
8. v. nautical To take in part of a sail in order to adapt the size of the sail to the force of the wind.
9. v. Australia To pull or yank strongly.

GNU Webster's 1913

1. n. A chain or range of rocks lying at or near the surface of the water. See Coral reefs, under coral.
2. n. (Mining.) A large vein of auriferous quartz; -- so called in Australia. Hence, any body of rock yielding valuable ore.
3. n. (Naut.) 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.
4. v. (Naut.) To reduce the extent of (as a sail) by rolling or folding a certain portion of it and making it fast to the yard or spar.

WordNet 3.0

1. v. reduce (a sail) by taking in a reef
2. n. one of several strips across a sail that can be taken in or rolled up to lessen the area of the sail that is exposed to the wind
3. n. a submerged ridge of rock or coral near the surface of the water
4. n. a rocky region in the southern Transvaal in northeastern South Africa; contains rich gold deposits and coal and manganese
5. v. roll up (a portion of a sail) in order to reduce its area
6. v. lower and bring partially inboard