A very common, well-known knot for fastening a rope to a spar, mooring-chain or cable (for example, it is often used to take the strain off a sheet with a riding turn on a winch). The strain must be on the standing part and be more or less constant, certainly constant in direction or the hitch will work loose. A hitch, by the way, is used for fastening a line to another object, usually a spar or chain, but is also used for fastening one rope to another in this way, ie. a hitch tied on the standing part rather than two ropes fastened together by a bend, e.g. sheet bend.