- (geometry) A line segment between any point on the circumference of a circle and its center/centre.
- (entomology) One of the major veins of the insect wing, between the subcosta and the media
- (zoology) The lighter bone (or fused portion of bone) in the forelimb of an animal.
- (geometry) The length of this line segment.
- (anatomy) The long bone in the forearm, on the side of the thumb.