A simple machine consisting of a wheel with a groove in which a rope can run to change the direction or point of application of a force applied to the rope WordNet 3.0 & Open English WordNet

A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and the cable or belt. Wikipedia

In sailing, a block is a single or multiple pulley. Wikipedia

Mechanical device used to transfer mechanical energy. Wikipedia Disambiguation

A single or multiple pulley used on sailboats Wikipedia Disambiguation

Type of simple machine; wheel on an axle or shaft fixed in a frame; used to change of direction of a cable Wikidata

Sailing term; single or multiple pulley Wikidata

A tool, consisting of a set of wheels around which a rope is led, meant to lift or move a load more lightly. OmegaWiki

One of the simple machines; a sheave, a wheel with a grooved rim, in which a pulled rope or chain lifts an object (more useful when two or more pulleys are used together, as in a block and tackle arrangement, such that a small force moving through a greater distance can exert a larger force through a smaller distance). Wiktionary

One of simple machines. Wiktionary (translation)

A shell containing one or more sheaves, the whole forming a pulley. Wiktionary