(anatomy) The long bone in the forearm, on the side of the thumb. / (zoology) The lighter bone (or fused portion of bone) in the forelimb of an animal.

(computing) Initialism of Remote Authentication Dial-In User Service.

(firearms) The distance between the front and rear sights of a firearm.

Synonym of radius bar / Synonym of radius arm

plural of radius bar

In a steam engine, a rod pivoted at one end and connected at the other with a concentrically moving part at a fixed distance.

plural of radius rod

(informal, astronomy) The radius of a celestial body when it is long enough to allow gravity to transform the body into a globe, typically estimated at approximately 300 kilometres.

(hydraulics, surface science) For a porous material, the ratio of porosity (ratio of volume of interstitial space filled with fluid to volume of material) to specific surface area (ratio of surface area in contact with fluid to volume of material); for a pipe or channel, the ratio of cross-sectional area to wetted perimeter.

(mathematics, for any point on a curve) The radius of the osculating circle at the point on the curve