noun
1.
a principle governing conduct, action, or procedure
found it hard to live by outdated laws
Synonyms: assize, canon, decree, decretum, edict, institute, ordinance, precept, prescript, prescription, regulation, rule, statute
Related Word: command, dictate, mandate
2.
Synonyms: principle 1, axiom, fundamental, principium, theorem
Related Word: exigency, necessity
Antonyms: chance