直径用英语怎么说

直径的英文是 "diameter". 这个词来自古希腊语，由 "dia" 和 "metron" 组成，分别表示 "through" 和 "measure"。因此，直径可以被定义为通过圆心穿过圆周的一条线段。

例句：

The diameter of the Earth is approximately 12,742 kilometers.
This tree has a diameter of about 30 centimeters at its base.
The diameter of a golf hole is typically around 4.25 inches.