principle
UK[ˈprɪnsəpəl]US[ˈprɪnsəpəl]
n
A fundamental truth or proposition that serves as the foundation for a system of belief or behavior or for a chain of reasoning.
n
A general scientific theorem or law that has numerous special applications across a wide field.
n
A rule or belief governing one's personal behavior.
Etymology
The word 'principle' entered English in the late 14th century via Old French principe, from the Latin principium, meaning "a beginning, origin, foundation, first part." This Latin term is built on princeps ("first man, chief, leader"), which combines primus ("first") and the root of capere ("to take"). Thus, the core etymological sense is "that which is taken first, the foundation." Over time, the meaning evolved from a physical or chronological "beginning" to an abstract, foundational source or fundamental truth upon which other things depend, capturing the logical sense of a primary axiom or rule from which a system proceeds.
Analysis
The word 'principle' is a simplex form in modern English. It is a loanword from Latin principium ("beginning, foundation, origin"), which itself is derived from princeps ("first, chief"). The morphemic elements (e.g., prin- related to 'first') are not transparently segmentable within the current English spelling without reverting to its Latin root form.
Examples
The principle of equality is central to democratic societies.
The device operates on the principle of magnetic levitation.
She refused to lie, as it was against her principles.