A wooden or metal bar or pin, used to support or steady anything.
A square bar of wood or iron, with a shoulder at one end, to support the weight of the topmast (on a ship).
A small thick piece of anything.
A plug of oakum for the vent of a gun.
The penis.
A pointed tool without any sharp edges, used in weaving or knotwork to tighten and form up weaves or complex knots; used in sailing ships to open the strands of a rope before splicing. Compare marlinespike.
To support a topmast using a fid.
A spike, wedge, or peg that is driven into a rock or ice surface as a support (as for a mountain climber).
To put pitons into a rock/ice to facilitate climbing.