FID

noun a block of wood used in mounting and dismounting heavy guns.

2. fid ·noun a wooden or metal bar or pin, used to support or steady anything.

3. fid ·noun a pin of hard wood, tapering to a point, used to open the strands of a rope in splicing.

4. fid ·noun a square bar of wood or iron, used to support the topmast, being passed through a hole or mortise at its heel, and resting on the trestle trees.