ring1

noun

• 1a small circular band, typically of precious metal and often set with one or more gemstones, worn on a finger as an ornament or a token of marriage, engagement, or authority.
• a circular band of any material:fried onion rings
• Astronomy a thin band or disk of rock and ice particles around a planet.
• a circular marking or pattern:black rings around her eyes
• short for tree ring.
• [usually as modifier] Archaeology a circular prehistoric earthwork, typically consisting of a bank and ditch:a ring ditch

• 2an enclosed space, typically surrounded by seating for spectators, in which a sport, performance, or show takes place:a circus ring
• a roped enclosure for boxing or wrestling.
• (the ring) the profession, sport, or institution of boxing.

• 3a group of people or things arranged in a circle:he pointed to the ring of trees
• (in a ring) arranged or grouped in a circle:everyone sat in a ring, holding hands
• [usually with modifier] a group of people drawn together due to a shared interest or goal, especially one involving illegal or unscrupulous activity:the police had been investigating the drug ring
• Chemistryanother term for closed chain.

• 4a circular or spiral course:they were dancing energetically in a ring

• 5 Mathematics a set of elements with two binary operations, addition and multiplication, the second being distributive over the first and associative.

verb

• 1surround (someone or something), especially for protection or containment:the courthouse was ringed with police
• form a line around the edge of (something circular):dark shadows ringed his eyes
• draw a circle around (something), especially to focus attention on it:an area of Tribeca had been ringed in red

• 2put a circular band through the nose of (a bull, pig, or other farm animal) to lead or otherwise control it.