Clamp n.
1. Something rigid that holds fast or binds things together; a piece of wood or metal, used to hold two or more pieces together.
2. (a) An instrument with a screw or screws by which work is held in its place or two parts are temporarily held together. (b) Joinery A piece of wood placed across another, or inserted into another, to bind or strengthen.
3. One of a pair of movable pieces of lead, or other soft material, to cover the jaws of a vise and enable it to grasp without bruising.
4. Shipbuilding A thick plank on the inner part of a ship's side, used to sustain the ends of beams.
5. A mass of bricks heaped up to be burned; or of ore for roasting, or of coal for coking.
6. A mollusk. See Clam. [Obs.]
Clamp nails, nails used to fasten on clamps in ships.