literally, to stop (snub) the motion of a rope (the sheet) that is moving through a pulley (the block). Snub is a nauticalterm for suddenly stopping the motion of something, such as a ship that has been going forward or the motion of a rope that is running through a hole or a channel. A sheet is a rope, wire or line attached to the sails of a ship and by which the position of the sail is adjusted. The sheet is threaded through a block, a casing, usually of wood, commonly found on vessels of all sizes and used to facilitate the working of ropes and lines. The block increases the mechanicalpower of the ropes by their use in various combinations. A sailor can snub a line by jamming the block by which it is running.