n. A low, narrow ridge of rocks, rising ordinarily but a few feet above the water.n. Any extensive elevation of the bottom of the sea; a shoal; abank: so called by fishermen.n. In Australia, the same as lode, vein, or ledge of the Cordilleran miner: as, a quartz-reef (that is, a quartz-vein).n. A kind of commercial sponge which grows on reefs.n. Nautical, a part of a sail rolled or folded up, in order to diminish the extent of canvas exposed to the wind.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.To gather up stuff of any kind in away similar to that described in def. 1. Compare reefing.See the quotation.Scabby; scurvy.n. The itch; also, any eruptive disorder.n. Dandruff.n. In the Tyrolese Alps, and especially in the region of the dolomites, “massive un-stratified limestones and dolomites rising amid strikingly contrasted sediments.”In Australian mining, to work at a reef.