a ring-shaped extension on the top of a can or tin, which one pulls to open it.

One of a pair or rings exchanged by bride and groom in a wedding ceremony, and afterwards worn by them; symbolizes continuous fidelity.

(cricket) An attacking ring of infielders, square and in front of the wicket - point, cover, mid off, mid on, midwicket, square leg.

(informal, idiomatic) To seem at least vaguely familiar. / (informal, idiomatic) To spark a previously forgotten memory. / Used other than figuratively or idiomatically: see ring, a, bell.

A ring or seal that fits around a piston, sealing between the piston and the bore in which it slides.

A circular arena in a circus, where the acts are performed.

(Britain) A form of civil protection (using closed-circuit television, control zones and restricted access) that effectively seals off city centres and financial districts; used in Northern Ireland and the City.

a network topology consisting of a physical star and a logical ring.

(computing) A network topology in which, in the physical case, every node of a network is connected to exactly two other nodes: one node designated as upstream and the other as downstream. A given node receives data from its upstream node and sends data to its downstream node.

(computing) A network standard invented by IBM and later defined by the 802.5 subcommittee of the IEEE which provides for a network with a star ring topology, and which operates by passing a token frame around the logical ring.