1. (n.) A source, or origin; a fundamental truth, proposition or law\.

2. (n.) Beginning; commencement.

3. (n.) An original faculty or endowment.

4. (n.) A fundamental truth; a comprehensive law or doctrine, from which others are derived, or on which others are founded; a general truth; an elementary proposition; a maxim; an axiom; a postulate.

5. (n.) A settled rule of action; a governing law of conduct; an opinion or belief which exercises a directing influence on the life and behavior; a rule (usually, a right rule) of conduct consistently directing one's actions; as, a person of no principle.

6. (n.) Any original inherent constituent which characterizes a substance, or gives it its essential properties, and which can usually be separated by analysis; -- applied especially to drugs, plant extracts, etc.

7. (v. t.) To equip with principles; to establish, or fix, in certain principles; to impress with any tenet, or rule of conduct, good or ill.

Procrustean law a belief a priori truth activity ambition antecedents article of faith aspiration at bottom attitude axiom base basement basically basis bearing wall bed bedding bedrock belief brocard call calling campaign canon causation cause cause and effect center code commandment commitment conscience consideration convention core credo creed criterion crusade determinant determinative dictate dictum doctrine dogma drive element elements elixir essence essential essentially ethic etiology factor faith floor flooring flower focus fond footing form formality formula formulary foundation fundament fundamental fundamentally fundamentals general principle gist given goal golden rule grammar gravamen great cause ground grounds groundwork guide guideline guiding light guiding principle guiding star hardpan heart honesty hypostasis idea ideal ideally imperative in essence in theory inner essence inspiration integrity intention interest issue kernel law law of nature lifework lodestar mainspring marrow mass movement matter maxim meat mitzvah model moral morality morals motive movement norm norma notion nub nucleus nuts and bolts occasion order of nature ordinance pavement philosophy pith point of view postulate precept prescribed form prescription principium principles probity proposition quid quiddity quintessence radical reason reason for being regulation riprap rock bottom rubric rudiment rudiments rule sake sap score seat self-evident truth sentiment set form settled principle sill solid ground solid rock soul source spirit spring standard standing order stereobate stimulus stuff stylobate substance substratum substruction substructure teaching tenet terra firma the nitty-gritty theorem theoretically truism truth ulterior motive underbuilding undercarriage undergirding underpinning understruction understructure universal law universal truth uprightness usage viewpoint vocation working principle working rule