swivel

A device that joins two parts in a way that allows one part to turn without turning the other.

To turn or rotate on a swivel or an axis.

To secure, fit, or support with a swivel.

To turn on a swivel or an axis.

To turn on or as on a staple, pin, or pivot.

To turn (anything) on or as on a swivel of any kind.

A fastening so contrived as to allow the thing fastened to turn freely round on its axis; a piece fixed to a similar piece, or to any body, by a pin or otherwise, so as to revolve or turn freely in any direction; a twisting link in a chain, consisting of a ring or hook ending in a headed pin which turns in a link of the chain so as to prevent kinking. See also cut under rowlock.

A gun mounted on a swivel or pivot: commonly, but not always, limited to very small and light guns so mounted.

A rest on the gunwale of a boat for supporting a piece of ordnance or other article that requires swinging in a horizontal plane.

A small gun on the deck of a fishing-schooner, used in foggy weather to signal to the dories the position of the vessel.