1) Knot 2) Knot for shortening a rope 3) Knot used to take up slack 4) Line-shortening knot 5) Rope-shortening knot 6) Type of knot 1) Knot 
The sheepshank is a type of knot that is used to shorten a rope or take up slack. This knot is not stable. It will fall apart under too much load or too little load. The knot has several features which allow a rope to be shortened: == Construction methods == A sheepshank knot may be constructed as follows: ... An alternative method for quickly con...
• (n.) A hitch by which a rope may be temporarily shortened.
(from the article `knot`) The sheepshank (K) is a simple knot useful for temporarily shortening a rope. It is made by making a double loop in the rope and tying a half hitch ...
Sheep'shank` noun (Nautical) A hitch by which a rope may be temporarily shortened. 
The sheepshank is a sailor's knot used to temporarily shorten a rope or to protect a damaged section of rope. The sheepshank has the disadvantage that it is easily shaken undone.
[n] - a knot for shortening a line
noun a knot for shortening a line