vt.

1. 解释，给……下定义
   Do you know who defined man as a rational animal?

   你知道是谁将人说成是有理智的动物的？

2. 规定，限定，使明确
   The powers of the courts are defined by law.

   法庭的权力是由法律规定的。

3. 确定……的界线；使……的轮廓分明
   The boundary is not clearly defined.

   这疆界没有明确划定。

4. 为……的特性，是……的特色[（+as）]
   Reason defines man.

   理性是人的特点。

v.

1. state or describe exactly the nature, scope, or meaning of.
   ▸give the meaning of (a word or phrase).
2. mark out the limits of.