mainsheet vs weather sheet

mainsheet and weather sheet both are nouns.

Word	Noun	Adjective	Verb	Adverb
mainsheet	Yes	No	No	No
weather sheet	Yes	No	No	No

As nouns, mainsheet and weather sheet are synonyms defined as:

mainsheet and weather sheet: (nautical) a line (rope or chain) that regulates the angle at which a sail is set in relation to the wind

Other synonyms of mainsheet include sheet, shroud, tack.

mainsheet (noun)	weather sheet (noun)
(nautical) a line (rope or chain) that regulates the angle at which a sail is set in relation to the wind	(nautical) a line (rope or chain) that regulates the angle at which a sail is set in relation to the wind