Pi is officially defined as the ratio of the circumference of a circle to its diameter.
The doctors discovered the entry wound into the frontal lobe with a diameter about equal to that of a cigarette.
Kepler-186f is about 11 percent larger than Earth in diameter, which means it has nearly 25% more surface area.
diameter di·am·e·ter (dī-ām'ĭ-tər)
A straight line connecting two opposite points on the surface of a spherical or cylindrical body, or at the boundary of an opening or foramen, passing through the center of such body or opening.
The distance measured along such a line.
The diameter of a graph is the maximum value of the minimum distance between any two nodes.