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