A chain or range of rocks lying at or near the surface of the water. See Coral reefs, under coral, a small rope formerly used to reef the courses by being passed spirally round the yard and through the holes of the reef, The itch; any eruptive skin disorder, verb_ roll up (a portion of a sail) in order to reduce its area, lower and bring partially inboard, reduce (a sail) by taking in a reef, transitive verb_ To reduce the size of (a sail) by tucking in a part and tying it to or rolling it around a yard, To shorten (a topmast or bowsprit) by taking part of it in, adjective_ Scabby; scurvy,