1) Stay 
On a sailing vessel, a backstay is the piece of standing rigging that runs from the mast to the transom of the boat, counteracting the forestay and jib. The backstay is an important sail trim control and has a direct effect on the shape of the mainsail and the headsail. ==Types of backstays== There are two general categories of backstay: The perma...
stay extending from ship's mastheads to the side of the ship
stay extending from ship's mastheads to the side of the ship
• (n.) A rope or stay extending from the masthead to the side of a ship, slanting a little aft, to assist the shrouds in supporting the mast. • (n.) A rope or strap used to prevent excessive forward motion.
A line running from the masthead to the stern to support the mast.
A rigging wire used to keep the mast from moving forward, as well as to vary the amount of bend in the mast. A permanent backstay goes to the transom. Running backstays go to each gunwhale.
a wire fixed to the mast running to the stern
Back'stay` (-stā`) noun [ Back , adjective or noun + stay .] 1. (Nautical) A rope or stay extending from the masthead to the side of a ship, slanting a little aft, to assist the shrouds in supporting the mast. [ Often used in the plural.] 2. A rope or strap us...
A wire-rope from the top of the mast leading aft to prevent the mast from bending forward. 
A mast support that runs from the top of the mast to the stern of the yacht; it may be adjustable in order to bend the mast backward or to increase tension on the forestay.
A wire support for the mast, usually running from the stern to the head of the mast.
[n] - a stay that supports the back of something
[Treasure Island] a stay (heavy rope or cable used for support) extending aft (toward the rear) from a masthead to the side or stern of a vessel.
noun a stay that supports the back of something
The back brace of a rigger that locks the pin in position to maintain pitch (not found on wing rigger boats).