n.

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

   我對此很認真。這是原則問題。

2. 主義；信條[C]
3. （機器等的）原理；構造；工作方式[C]
   The two machines work on the same principle.

   這兩部機器的工作原理是一樣的。

4. 道義，節操[U]
   He is a man of high principle.

   他是節操高尚的人。

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.