Lin″er (līn″ẽr), n. 1. One who lines, as, a liner of shoes.
2. A vessel belonging to a regular line of packets; also, a line-of-battle ship; a ship of the line.
3. (Mach.) A thin piece placed between two parts to hold or adjust them, fill a space, etc.; a shim.
4. (Steam Engine) A lining within the cylinder, in which the piston works and between which and the outer shell of the cylinder a space is left to form a steam jacket.
5. A slab on which small pieces of marble, tile, etc., are fastened for grinding.
6. (Baseball) A ball which, when struck, flies through the air in a nearly straight line not far from the ground.