adj.主要的；首要的
n.本金；资本；校长；主角；委托人；主犯
Our principal problem is lack of time. 我们的主要问题就是缺少时间。
My wages are the principal source of my income. 薪金是我收入的主要来源。
My principal concern is my family's welfare. 我至为关心的是我一家的幸福。
用作名词 (n.)How much interest will there be on a principal of $5000? 5000美元本金的利息是多少？
The principal or capital,as distinguished from the interest or income,as of a fund or estate. 资金，基金或资产的本金或资本，以区别于利息或收入。
When I came into the office, the principal rose to welcome me. 当我走进办公室时,校长起身欢迎我。
He is going to fill the position of principal. 他将去担任中学校长的职务。
She danced the principal role in the ballet. 她在这个芭蕾舞中担任主角。
Through it all Richard Nixon moved as if he were himself a spectator, not the principal. 尼克松自始至终表现得象旁观者，而不是主角。
The agent spoke on behalf of his principal. 代理人代表他的委托人说话。
I will have to consult my principals before I can give you an answer on that. 我必须同我的委托人磋商后才能就这个问题给你答复。
Indeed I was the principal in the crime. 我真正做了这个罪恶的主犯。
Shall I work underground, bribing the paltry assistants in that foul conspiracy, until I find my way to the thrice guilty principal? 我要不要秘密进行追究，贿赂那肮脏密谋中的可鄙助手，直至我找到线索挖出那三倍有罪的主犯？
principal同principle的比较：两者的发音相同。principal作为形容词时，意思为“主要的”“最重要的”。 principal作为名词时意为“校长”。 而principle的意思为“科学定律或者是到个规范”。 What's your principal reason for wanting to be a writer？ If you want to leave early you'll have to ask the Principal. He's a boy with very strong principles.
principal作为校长时，各地区用法不尽相同：在英国常表示牛津（Oxford)和剑桥（Cambridge)大学的若干学院（college)的院长，或是若干大学的校长。在美国仅仅只是表示中学或小学校长。而在苏格兰表示的是大学校长。
adj.(形容词)principal用作形容词的意思是“最重要的,主要的,首要的”,用于人时指其起的作用最大,而不指职位最高; 用于物时,指其在重要性上优于他物,起决定作用。
principal无比较级和最高级形式。
