(1)原理(则) (basic truth that underlies sth) [C][N(of)]： the～s of geometry/navigation/political economy/psychology/cooking/Christianity 几何学/航海学/政治经济学/心理学/烹调/基督教原理;the～of freedom of speech/equality of opportunity for all 言论自由/机会均等的原则;the～of Archimedes 阿基米德定律;the first～s 基本原理;〖同〗rule，truth，law;

(2)行为的准则(规范) (general rule or standard of (usu good) behaviour) [C， 通常pl; U][N(of)]： live up to/according to one's～s 按自己的行为准则行事;abandon one's～s 放弃自己的行为准则;～s of conduct 行为准则;moral～s 道德准则;a man of high～(s) 有高度道德原则的人;He seems to have no～s at all when it is a question of making money. 遇到赚钱的问题时，他好像一点都不讲道德。They are quite without～. 他们很不讲道德。It's against her～s to lie. 说谎违背了她的行为准则。It is a matter of～with sb to do... 做……对某人来说关系到做人的大问题。

(3)(机器等的)工作原理 (theory by which a machine， etc works) [C， 通常 sing][N(of)]： the～of the jet engine/acceleration 喷气发动机/加速度原理;These machines work/A bicycle and a motorcycle are built on the same～. 这些机器工作原理相同/自行车和摩托车的制造原理相同。

in principle 1)从理论上讲，按道理： We expect it to work in～but we've yet to try. 按道理讲我们认为它能工作，但我们还得试一试。2)原则上，大体上，基本上： I agree with you in～but I'd like to discuss a few details. 我原则上同意你的意见，但是我想讨论几个细节问题。

on principle 由(出)于自己的道德观念或信仰： We disagree with all violence on～. 从道德观念上讲，我们不赞成任何暴力。

→′principled adj 原则(性)的，有原则(性)的