Diameter

ony straicht line segment that passes throu the centre o the circle an whose endpynts lie on the circle
Circle wi circumference (C) in black, diameter (D) in cyan, radius (R) in reid, an centre or origin (O) in magenta.

In geometry, a diameter o a circle is ony straicht line segment that passes throu the centre o the circle an whose endpynts lie on the circle.