'mainsheet' definitions:

Definition of 'mainsheet'

(from WordNet)
noun
(nautical) a line (rope or chain) that regulates the angle at which a sail is set in relation to the wind [syn: sheet, tack, mainsheet, weather sheet, shroud]

Definition of 'mainsheet'

From: GCIDE
  • mainsheet \main"sheet`\, n. (Naut.) One of the ropes by which the mainsail is hauled aft and trimmed. [1913 Webster]