Law, rule, regulation, precept, statute, ordinance, canon all designate a principle laid down or accepted as governing conduct, action, or procedure.
Law, rule, and precept are also used as collective nouns to denote a body of laws, rules, or precepts. Law and precept are often used abstractly.
Law (see also HYPOTHESIS ) primarily implies imposition by a sovereign authority and the obligation of obedience on the part of those governed. In more restricted use, however, it implies a will to maintain peace and justice in the community or group governed and the expression of that will in concrete injunctions or prohibitions. Laws may be written or unwritten: when unwritten they indicate derivation from established custom; when written they commonly indicate enactment by a legislative body or power.
Rule , in contrast with law , suggests closer relation to individual conduct and method, or a desire for order and discipline in the group. Sometimes it implies restriction, whether prescribed or self-imposed, for the sake of an immediate end (as unity in action, uniformity in procedure, or conformity to a standard of practice). Sometimes rule does not imply ordering and prohibiting but suggests a positive way of thinking or acting in order to get desired or concrete results.
Regulation often equals rule, but distinctively it connotes prescription by authority for the control or management of an organization or system.
Precept, like law, usually implies generality and lack of detail in the statement and an authoritative origin; like rule, however, it implies closer reference to individual conduct than to government. Often precept is applied to what is enjoined by teaching; it commonly suggests counsel or advice, and is opposed in its abstract use to practice or example. Statute, ordinance, and canon all come under the general class of law.
A statute is a written law, formally enacted by a legislative body.
An ordinance is a local law, especially one enacted by a municipal government.
A canon, basically, is a law of a church binding upon all of its members. In extended use canon is applied to such laws of ethics, of society, of criticism, and of the practice of the arts, as have the sanction of accepted authority and are enforced by one's moral, social, or artistic conscience.