A radius is a straight line or distance from the center to the edge of a curve.

Radius may also refer to:

People

  • Alexandra Radius (born 1942), Dutch ballerina
  • Justus Radius (1797–1884), German pathologist and ophthalmologist
  • Radius Prawiro (1928–2005), Indonesian economist and politician

Arts, entertainment, and media

Fictional entities

  • Radius (Chrono Cross), a character in Chrono Cross
  • Radius (comics), a superhero in the Marvel Comics universe
  • Radius (R.U.R.), a character in Karel Čapek's science fiction play R.U.R.

Film

  • Radius (film), a 2017 Canadian film directed by Caroline Labrèche and Steeve Léonard

Music

  • Radius (music ensemble), a London music ensemble founded by Tim Benjamin

Companies

  • Radius Inc., a defunct computer hardware company
  • Radius Intelligence, a defunct enterprise software company
  • Radius Payment Solutions, a payment and fleet services technology and software company
  • Radius Travel, a travel management company

Mathematics

  • Radius (graph theory), the minimum distance from a graph's node to the node that is furthest from it
  • Radius of convergence (in calculus), the radius of the region where a complex power series converges
  • Radius of curvature, a measure of how gently a curve bends
  • Radius of gyration, the root-mean-square distance from a set of points or masses to a given center
  • The radial coordinate in a
  • Polar coordinate system (2D)
  • Cylindrical coordinate system (3D)
  • Spherical coordinate system (3D)
  • The inradius or circumradius of a shape

Science and technology

  • Radius (bone), one of the two bones in a forearm
  • Bend radius, the minimum radius to which one can bend a pipe, tube, sheet, cable, or hose without damage
  • RADIUS (Remote Authentication Dial In User Service), a network authentication protocol
  • Turning radius, the minimum radius at which a vehicle can negotiate a turn