All articles starting with R
22,461 articles
Ring galaxy
A ring galaxy is a galaxy with a prominent ring of stars and gas, often formed when a smaller galaxy passes through a larger one's disk.
Ring game
A ring game, also called a ring play, is a circle game with singing, dance movements, or mime, played chiefly in African-American and Caribbean children's traditions.
Ring gyroscope
A ring gyroscope is a Coriolis vibratory gyroscope that senses rotation with a ring-shaped resonator, first micromachined by Putty and Najafi in 1994 and now manufactured by Silicon Sensing Systems.
Ring homomorphism
A ring homomorphism, also called a ring morphism, is a function between rings that preserves addition and multiplication, with kernel and image governed by the isomorphism theorems.
Ring Lardner
Ring Lardner (Ringgold Wilmer Lardner, 1885-1933), American sportswriter, columnist, and satirical short-story writer, author of You Know Me Al and the Jack Keefe baseball letters, famed for his ear for American vernacular speech.
Ring laser
A ring laser is a laser whose resonator is a closed loop of optical path rather than two end mirrors, operating unidirectionally for single-frequency output or bidirectionally as a gyroscope.
Ring laser gyroscope
A ring laser gyroscope, or RLG, is a rotation sensor using the Sagnac effect: two counter-propagating laser beams in a ring cavity reveal rotation through their frequency difference.
Ring main unit
A ring main unit (RMU) is a compact, factory-assembled switchgear unit used at load points of a ring distribution network, typically rated 11 to 24 kV.
Ring modulator
A ring modulator, also called a lattice modulator or double-balanced mixer, is a frequency-mixing circuit named for its ring of four diodes, producing sum- and difference-frequency outputs.
Ring My Bell
Ring My Bell: 1979 disco song written and produced by Frederick Knight, sung by Anita Ward on Juana/T.K. Records; Hot 100, UK, and Canadian number one, her only major hit, revived by a 2026 TikTok trend.
Ring name
Ring name: a professional wrestler's stage name for their character, central to kayfabe and branding; often trademarked by promotions like WWE, which typically own names created under contract, though performers like The Rock have reclaimed them.
Ring Nebula
The Ring Nebula (Messier 57, NGC 6720) is a planetary nebula in Lyra, the glowing gas shell of a dying sun-like star about 2,600 light-years from Earth.
Ring network
A ring network is a network topology in which each node connects to two adjacent nodes in a closed loop, often using token passing to control transmission.
Ring of Brodgar
Ring of Brodgar: Neolithic stone circle and henge on Mainland Orkney, Scotland; 104 m circle of originally 60 stones (36 survive), rock-cut ditch 136 m across, built around 2600–2400 BC, scheduled 1882.
Ring of Fire
Ring of Fire (Pacific Ring of Fire): popular name for the circum-Pacific belt of subduction-zone volcanoes and earthquakes, not a scientific term. Holds 687 Holocene volcanoes (57% of world total) and about 81% of the largest earthquakes; first named by Carl Ritter in 1859.
Ring of Fire (song)
Ring of Fire: 1963 country song written by June Carter and Merle Kilgore, recorded by Johnny Cash; seven weeks at country No. 1, US pop No. 17, RIAA Gold, distinguished by mariachi-style horns.
Ring of Gyges
The Ring of Gyges, also called the ring of Giges (Anel de Giges), is Plato's Book II Republic thought experiment: an invisibility ring lets a Lydian shepherd murder the king and usurp the throne, posing Glaucon's challenge about justice under impunity.
Ring of Honor
Ring of Honor (ROH) is an American professional wrestling promotion founded in 2002, later owned by Sinclair Broadcast Group and acquired by Tony Khan in March 2022, known for its Code of Honor, Pure rules matches, and HonorClub streaming show.
Ring of integers
The ring of integers of a number field K is the subring of algebraic integers in K, generalizing the ordinary integers and central to algebraic number theory.
Ring of Kerry
Ring of Kerry: roughly 179 km circular scenic drive around the Iveragh Peninsula, County Kerry, Ireland, from Killarney via Kenmare, Sneem, Waterville, and Cahersiveen; part of the Wild Atlantic Way, with the Skellig Ring detour to UNESCO-listed Skellig Michael.
Ring of the Fisherman
The Ring of the Fisherman, also called the Fisherman's Ring, is the signet ring presented to each newly elected pope, bearing Saint Peter and the pope's name.
Ring oscillator
A ring oscillator is a digital circuit of an odd number of inverters in a loop that oscillates, used as a clock generator and chip speed probe.
Ring polymer melts
A ring polymer melt is a dense liquid of unknotted, nonconcatenated cyclic polymers whose closed loops cannot reptate, giving self-similar, power-law stress relaxation without a rubbery plateau.
Ring polymer molecular dynamics
Ring polymer molecular dynamics (RPMD) is an approximate quantum simulation method that represents each quantum particle as a classical ring polymer of spring-joined replicas, capturing tunneling and zero-point energy.
Ring rain
Ring rain is the flow of charged water particles from Saturn's rings along magnetic field lines into its upper atmosphere, first confirmed by Keck observations in 2013.
Ring Ring (album)
Ring Ring, ABBA's 1973 debut album, released in Sweden March 26, 1973 as Björn & Benny, Agnetha & Frida; recorded 1972–73; title track third in the 1973 Swedish Eurovision selection.
Ring rolling
Ring rolling is a metal forming process that expands a pierced, doughnut-shaped blank between rolls, increasing diameter while reducing wall thickness to produce seamless rings.
Ring seismology
Ring seismology, also known as kronoseismology, is a method of planetary seismology that reads a planet's internal oscillations from waves they raise in its rings.
Ring signature
A ring signature is a digital signature scheme letting a signer prove that some member of an ad hoc group signed a message without revealing which member it was.
Ring singularity
A ring singularity is the curvature singularity of the Kerr spacetime describing rotating black holes: it lies on a circle in the equatorial plane rather than a point.