first principle

American  

noun

1. any axiom, law, or abstraction assumed and regarded as representing the highest possible degree of generalization.

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first principle British  

noun

1. one of the fundamental assumptions on which a particular theory or procedure is thought to be based

2. an axiom of a mathematical or scientific theory

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Example Sentences

First principle: Orders are presumed to be lawful, but that presumption is rebuttable rather than conclusive.

From Slate • Nov. 24, 2025

Therefore the following seven principles ought to be accepted: First principle: The League of Nations is composed of all civilised States which recognise one another's external and internal independence and absolute equality before International Law.

From The League of Nations and its Problems Three Lectures by Oppenheim, L. (Lassa)

First principle: the annual crop is borne only on canes of the same year's growth, springing from wood of the previous season's growth.

From Home Vegetable Gardening — a Complete and Practical Guide to the Planting and Care of All Vegetables, Fruits and Berries Worth Growing for Home Use by Rockwell, F. F. (Frederick Frye)