pul·ley (po?ol??)n. pl. pul·leys 1. A simple machine consisting essentially of a wheel with a grooved rim in which a pulled rope or chain can run to change the direction of the pull and thereby lift a load.2. A wheel turned by or driving a belt.[Middle English poley, from Old French polie and from Medieval Latin poliva, both ultimately from Greek polos, axis; see kwel- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.pulley (?p?l?) n1. (Mechanical Engineering) a wheel with a grooved rim in which a rope, chain, or belt can run in order to change the direction or point of application of a force applied to the rope, etc2. (Mechanical Engineering) a number of such wheels pivoted in parallel in a block, used to raise heavy loads3. (Mechanical Engineering) a wheel with a flat, convex, or grooved rim mounted on a shaft and driven by or driving a belt passing around it[C14 poley, from Old French polie, from Vulgar Latin polidium (unattested), apparently from Late Greek polidion (unattested) a little pole, from Greek polos axis]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014pul?ley (?p?l i) n., pl. -leys. 1. a wheel for supporting, guiding, or transmitting force to or from a moving rope or cable that rides in a groove in its edge. 2. a combination of such wheels in a block, or of such wheels or blocks in a tackle, to increase the force applied. [1275?1325; Middle English poley, puly