reef

Definition
(noun) a submerged ridge of rock or coral near the surface of the water Definition
(noun) a rocky region in the southern Transvaal in northeastern South Africa; contains rich gold deposits and coal and manganese Definition
(noun) 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 Definition
(verb) lower and bring partially inboard Definition
(verb) roll up (a portion of a sail) in order to reduce its area Definition
(verb) reduce (a sail) by taking in a reef