1 [C,U] a rule for good behaviour, based on what a person believes is right 原则;行为准则:
He doesn't eat meat on principle.他依照原则不吃肉。She refuses to wear fur. It's a matter of principle with her.她拒绝穿毛皮,对她来说,那是个原则问题。
2 [C] a basic general law, rule or idea 原理;定律:
The system works on the principle that heat rises.那系统根据热空气上升的原理运作。The course teaches the basic principles of car maintenance.这门课程教授汽车保养的基本原理。
in principle in general, but possibly not in detail 基本上;大体上:
His proposal sounds fine in principle, but there are a few points I'm not happy about.他的建议听起来大体上不错,但有几点我不太满意。