swivel

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A device that joins two parts in a way that allows one part to turn without turning the other.
• intransitive verb To turn or rotate on a swivel or an axis.
• intransitive verb To secure, fit, or support with a swivel.
• intransitive verb To turn on a swivel or an axis.

from The Century Dictionary.

• To turn on or as on a staple, pin, or pivot.
• To turn (anything) on or as on a swivel of any kind.
• noun 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.
• noun A gun mounted on a swivel or pivot: commonly, but not always, limited to very small and light guns so mounted.
• noun A rest on the gunwale of a boat for supporting a piece of ordnance or other article that requires swinging in a horizontal plane.
• noun A small gun on the deck of a fishing-schooner, used in foggy weather to signal to the dories the position of the vessel.
• noun A diminutive shuttle used in the figure-weaving of silk, etc., and moved to and fro by slides or by hand.
• noun A small shuttle for use in a swivel-loom for weaving ribbons.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To swing or turn, as on a pin or pivot.
• noun (Mech.) A piece, as a ring or hook, attached to another piece by a pin, in such a manner as to permit rotation about the pin as an axis.
• noun (Mil.) A small piece of ordnance, turning on a point or swivel; -- called also swivel gun.
• noun a kind of drawbridge that turns round on a vertical axis; a swing bridge.
• noun a hook connected with the iron strap of a pulley block by a swivel joint, for readily taking the turns out of a tackle.
• noun a joint, the two pieces composing which turn round, with respect to each other, on a longitudinal pin or axis, as in a chain, to prevent twisting.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mechanical : A piece, as a ring or hook, attached to another piece by a pin, in such a manner as to permit rotation about the pin as an axis.
• noun military A small piece of ordnance, turning on a point or swivel; called also swivel gun.
• noun slang strength of mind or character that enables one to overcome adversity; confidence; will
• verb intransitive To swing or turn, as on a pin or pivot.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb turn on a pivot
• noun a coupling (as in a chain) that has one end that turns on a headed pin