n.[C]

1. 直徑
   Measure the diameter of this circle.

   量一下這圓的直徑。

2. 倍（透鏡等的放大單位）
   This glass magnifies 20 diameters.

   這個放大鏡能放大二十倍。

n.

1. a straight line passing from side to side through the centre of a body or figure, especially a circle or sphere.
   ▸a transverse measurement of something; width or thickness.
2. a unit of linear measurement of magnifying power.