Clamp

n. [L. Ger. & D. klamp, Dan. klampe, from D. klampen, to fasten, clasp. Cf. CRAMP, 3.]

1. Something that fastens or binds; a piece of timber or iron, used to fasten work together.
2. (Joinery.) (a.) An instrument with a screw or screws by which work is held in its place or together. (b.) A piece of wood placed across another, or inserted into another, to bind or strengthen.
3. A mass of bricks heaped up to be burned; or of ore heaped up to be smelted; or of coal heaped together to be converted to coke.
4. A kind of small bivalve shell-fish; a clam. [Obs.] See CLAM.
5. (Ship-building.) A thick plank on the inner part of a ship’s side, used to sustain the ends of the beams.
6. One of a pair of movable pieces of lead, or other soft material, to cover the jaws of a vise;—used to hold objects that would be injured by the vise itself.
7. A heavy footstep; a tramp.

Clamp nails, nails used to fasten on clamps in ships.