Note: The mainsail of a ship is extended upon a yard attached to the mainmast, and that of a sloop or schooner upon the boom.
MAINSHEET
Main"sheet`, n. (Naut.)
Defn: One of the ropes by which the mainsail is hauled aft and trimmed.
MAINSPRING
Main"spring`, n.
Defn: The principal or most important spring in a piece of mechanism, especially the moving spring of a watch or clock or the spring in a gunlock which impels the hammer. Hence: The chief or most powerful motive; the efficient cause of action.
MAINSTAY
Main"stay`, n.
1. (Naut.)
Defn: The stay extending from the foot of the foremast to the maintop.
2. Main support; principal dependence. The great mainstay of the Church. Buckle.
MAINSWEAR Main"swear`, v. i. Etym: [AS. manswerian to forswear; man sin, crime + swerian to swear.]