principleprin·ci·ple /ˈprɪnsəpəl/ noun1[countableC, uncountableU] a moral rule or set of ideas that makes you behave in a particular wayThe single European market works on market principles.
As a matter of principle (=a rule that is very important and that should not be broken), disabled people should have the right to work.
→ see also error of principle 2[countableC] a rule that explains how something works, or an idea that something is based onThe basic principle is that all information collected for one purpose is confidential.
The US market is built on the principle that a marketplace should be available to everyone.
accounting practice based on the accruals principle
→ ability-to-pay principle → accounting principle → benefit principle3in principle if something is possible in principle, there is no reason why it should not happen, but it has not actually happened yetIn principle, we pay all our freelance staff within one month.
4in principle if something happens in principle, decisions, rules etc say that it should happen, even if in practice it does not always happenIn principle, a hostile takeover is possible, but we want to discourage it.
5in principle if you agree to do something in principle, you agree in a general way to the idea or plan, without agreeing to any detailsNorth and South Korea agreed in principle to link their separate air-traffic control systems.