pulley vs fairlead

pulley and fairlead both are nouns.

Word	Noun	Adjective	Verb	Adverb
pulley	Yes	No	No	No
fairlead	Yes	No	No	No

As nouns, fairlead is a hyponym of pulley; that is, fairlead is a word with a more specific, narrower meaning than pulley:

pulley: 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
fairlead: a pulley-block used to guide a rope forming part of a ship's rigging to avoid chafing

Other hyponyms of pulley include bollock, bullock block, idle pulley, idle wheel, idler pulley.

pulley (noun)	fairlead (noun)
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	a pulley-block used to guide a rope forming part of a ship's rigging to avoid chafing