Definition of backstay in English English dictionary
A part of the rigging of a sailing ship extending from masthead the top of the mast to the back of the ship; they support the strain on all upper masts and provide additional support to the shrouds when the wind is abaft the beam
{i} rope or shroud extending from the top of a mast back to a ship's side or stern to help support the mast (Nautical); supporting device at or for the back of something (Machinery)