[reef] n [ME riff, fr. ON rif; akin to OE ribb rib] (14c) 1: a part of a sail taken in or let out in regulating size
2: reduction in sail area by reefing
[2]reef vt (1667) 1: to reduce the area of (a sail) by rolling or folding a portion
2: to lower or bring inboard (a spar) wholly or partially ~ vi: to reduce a sail by taking in a reef -- reef.able adj [3]reef n [D rif, prob. of Scand origin; akin to ON rif reef of a sail] (1584) 1 a: a chain of rocks or coral or a ridge of sand at or near the surface of water b: a hazardous obstruction
2: lode, vein -- reefy adj