n.

1. 原则；原理[C]
   I take this seriously. It's a matter of principle.

   我对此很认真。这是原则问题。

2. 主义；信条[C]
3. （机器等的）原理；构造；工作方式[C]
   The two machines work on the same principle.

   这两部机器的工作原理是一样的。

4. 道义，节操[U]
   He is a man of high principle.

   他是节操高尚的人。

5. 起源，本源

n.

1. a fundamental truth or proposition serving as the foundation for belief or action.
   ▸a rule or belief governing one's personal behaviour.
   ▸morally correct behaviour and attitudes:

   a man of principle.
2. a general scientific theorem or natural law.
3. a fundamental source or basis of something.
   ▸a fundamental quality or attribute.
4. Chemistry  an active or characteristic constituent of a substance.