n. & v.
n. a coupling between two parts enabling one to revolve without turning the other.
v.tr. & intr. (swivelled, swivelling; US swiveled, swiveling) turn on or as on a swivel. swivel chair a chair with a seat able to be turned horizontally.
[ ME f. weak grade swif- of OE swifan sweep + -LE(1): cf. SWIFT ]