All articles starting with R
22,461 articles
Roller skating
Roller skating, traveling on quad (2x2 wheel) or inline skates, began with a 1743 stage act and Merlin's 1760 skates; Plimpton's 1863 quad design made it a mass pastime, now governed by World Skate.
Roller skiing
Roller skiing, or skirolling, is off-snow cross-country skiing on short two-wheeled skis. Originating in 1930s Italy, it is the main summer training tool for cross-country and biathlon athletes and an FIS discipline with its own World Cup.
Roller sports (roller skating)
Roller sports (roller skating): wheeled skating sports governed by World Skate, including speed skating, artistic skating, inline hockey, roller derby, and inline freestyle; quad versus inline skates, World Games and Olympic history, and injury epidemiology.
Roller sports (skateboarding)
Roller sports (skateboarding): a judged trick-riding discipline of World Skate, the IOC-recognized roller sports federation. Street and park events for men and women; Olympic since Tokyo 2020, with Paris 2024 and Los Angeles 2028 confirmed.
Roller Track (Salihorsk)
Ролер трэк (roller track) is a World Skate-standard roller-sport circuit with parabolic banked turns on the embankment of Salihorsk, Belarus, with an inner skate park; described as the first such track in the post-Soviet space.
Roller-compacted concrete
Roller-compacted concrete (RCC), also known as rollcrete, is a dry, zero-slump concrete placed in layers with earthmoving equipment and compacted by vibratory rollers, widely used for concrete gravity dams and heavy-duty pavements.
Roller-compacted concrete dam
A roller-compacted concrete dam is a concrete gravity dam built by placing dry concrete in horizontal layers compacted with vibratory rollers, cutting costs 25 to 40 percent.
Roller-delayed blowback
Roller-delayed blowback is a firearm operating principle in which rollers impose a mechanical disadvantage that delays the bolt, used in the CETME, the Heckler & Koch G3, and the MP5.
Roller-integrated compaction
Roller-integrated compaction, originating in Europe as continuous compaction control and now called intelligent compaction, lets vibratory rollers measure soil stiffness in real time using accelerometers and GPS.
Roller-Walker
Roller-Walker (ローラーウォーカー) is a leg-wheel hybrid quadruped developed by Shigeo Hirose at the Tokyo Institute of Technology in 1995, which walks on rugged terrain and skates on smooth ground.
Rollerball (1975 film)
Rollerball (1975), also known from Harrison's story "Roller Ball Murder," is Norman Jewison's dystopian sci-fi film starring James Caan as Jonathan E., a champion of a violent corporate-run sport in 2018 who resists his masters.
Rollerball (2002 film)
Rollerball (2002) is John McTiernan's remake of Norman Jewison's 1975 dystopian sports film, based on William Harrison's "Roller Ball Murder." Set in 2005 Central Asia, it stars Chris Klein, LL Cool J, and Jean Reno, grossed $25.9 million on a $70 million budget, and holds a 3% Rotten Tomatoes score.
RollerCoaster Tycoon
RollerCoaster Tycoon, Chris Sawyer's 1999 theme park construction and management sim published by Hasbro Interactive, spawned RCT2 (2002) and RCT3 (2004); Atari's later entries faltered, with Wonderworks announced in 2026.
RollerCoaster Tycoon Wonderworks
RollerCoaster Tycoon Wonderworks (also styled Rollercoaster Tycoon: Wonderworks) is an upcoming theme park management game by Springloaded, published by Atari, announced at Gamescom 2026 for Steam Early Access on PC, with two parks, 60+ rides, and a chaotic physics engine.
RollerCoaster Tycoon World
RollerCoaster Tycoon World (RCTW), 2016 theme park sim by Nvizzio Creations and Atari, fourth mainline RCT entry; spline coaster editor, Steam Workshop, launched one day before Planet Coaster to Mostly Negative reviews (26% of 1,980).
Rolleston Coal Mine
The Rolleston Coal Mine, marketed as Rolleston Open Cut, is a large open-cut thermal coal mine in Queensland's Bowen Basin, mining since 2005 and owned by Glencore.
Rollie Fingers
Rollie Fingers (Roland Glen Fingers, born 1946) is a Hall of Fame relief pitcher for the Athletics, Padres, and Brewers; record 341 saves, 1981 AL MVP and Cy Young, 1974 World Series MVP.
Rollin Hotchkiss
Rollin Hotchkiss, fully Rollin Douglas Hotchkiss, was an American biochemist and geneticist at Rockefeller Institute whose purification of pneumococcal transforming DNA helped establish DNA as the genetic material.
Rollin Thomas Chamberlin
Rollin Thomas Chamberlin (1881–1948) was an American geologist, professor at the University of Chicago, known for the rock-dust method of preventing coal-dust explosions and studies of glacier motion.
Rollin' (Limp Bizkit song)
Rollin' (Air Raid Vehicle), 2000 Limp Bizkit single from Chocolate Starfish; UK No. 1 single, MTV VMA-winning World Trade Center video, Swizz Beatz Urban Assault Vehicle remix, one billion Spotify streams in 2026.
Rollin' Justin
Rollin' Justin is a wheeled humanoid research robot built by the German Aerospace Center (DLR), first presented in 2008 for mobile manipulation in household and space settings.
Rolling (metalworking)
Rolling, or metal rolling, is a metalworking process that reduces or shapes metal stock by passing it between rotating rolls, performed either hot or cold.
Rolling blackout
A rolling blackout, also called loadshedding, is a deliberate, rotating shutdown of power to blocks of customers to keep demand from exceeding supply and protect the grid.
Rolling circle amplification
Rolling circle amplification (RCA) is an isothermal enzymatic method that copies a circular DNA or RNA template into long tandem-repeat strands, used for biosensing and single-molecule counting.
Rolling circle replication
Rolling circle replication: genome copying of circular DNA or RNA templates producing head-to-tail concatemers, seen in plasmids, phages like lambda, viroids (asymmetric Pospiviroidae, symmetric Avsunviroidae), and HDV.
Rolling coal
Rolling coal, also called rolling coal, is the practice of modifying a diesel truck to emit large plumes of black exhaust smoke at other road users.
Rolling contact kinematics
Rolling contact kinematics is the branch of mechanics describing how two bodies in contact roll without slipping, supplying the nonholonomic constraint equations used to plan in-hand manipulation and wheeled locomotion.
Rolling forecast
A rolling forecast is a financial forecast that always extends a fixed number of periods ahead and is updated monthly or quarterly as actual results replace the forecast.
Rolling horizon optimization
Rolling horizon optimization is a decision method that repeatedly solves an optimization model over a moving time window, implementing only immediate decisions before re-solving as new information arrives.
Rolling in the Deep
Rolling in the Deep, Adele's lead single from 21 (2011), written with Paul Epworth; seven weeks at Billboard Hot 100 number 1, biggest US hit of 2011, UK peak number 2, and winner of the 2012 Grammys for Record and Song of the Year.