reef

nouns

a submerged ridge of rock or coral near the surface of the water
reef
is derived from
reefy
is a type of (narrower)
a long narrow natural elevation or striation
ridge
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
reef
is a part of
a large piece of fabric (usually canvas fabric) by means of which wind is used to propel a sailing vessel
canvas, canvass, sail, sheet
is a type of (narrower)
artifact consisting of a narrow flat piece of material
slip, strip

verbs

lower and bring partially inboard
"reef the sailboat's mast"
reef
is a type of (narrower)
move something or somebody to a lower position
"take down the vase from the shelf"
bring down, get down, let down, lower, take down
roll up (a portion of a sail) in order to reduce its area
reef
is a type of (narrower)
form into a cylinder by rolling
"Roll up the cloth"
furl, roll up
reduce (a sail) by taking in a reef
reef
is a type of (narrower)
reduce in size; reduce physically
"Hot water will shrink the sweater"; "Can you shrink this image?"
reduce, shrink