law 
(lô)
(lô)n.
Idioms: 1. A rule of conduct or procedure established by custom, agreement, or authority.
2.
a. The body of rules and principles governing the affairs of a community and enforced by a political authority; a legal system: international law.
b. The condition of social order and justice created by adherence to such a system: a breakdown of law and civilized behavior.
3. A set of rules or principles dealing with a specific area of a legal system: tax law; criminal law.
4.
a. A statute, ordinance, or other rule enacted by a legislature.
b. A judicially established legal requirement; a precedent.
5.
a. The system of judicial administration giving effect to the laws of a community: All citizens are equal before the law.
b. Legal action or proceedings; litigation: submit a dispute to law.
c. An impromptu or extralegal system of justice substituted for established judicial procedure: frontier law.
6.
a. An agency or agent responsible for enforcing the law. Often used with the: "The law ... stormed out of the woods as the vessel was being relieved of her cargo" (Sid Moody).
b. Informal A police officer. Often used with the.
7.
a. The science and study of law; jurisprudence.
b. Knowledge of law.
c. The profession of an attorney.
8. Something, such as an order or a dictum, having absolute or unquestioned authority: The commander's word was law.
9. Law
a. A body of principles or precepts held to express the divine will, especially as revealed in the Bible.
b. The first five books of the Hebrew Scriptures.
10. A code of principles based on morality, conscience, or nature.
11.
a. A rule or custom generally established in a particular domain: the unwritten laws of good sportsmanship.
b. A way of life: the law of the jungle.
12.
a. A statement describing a relationship observed to be invariable between or among phenomena for all cases in which the specified conditions are met: the law of gravity.
b. A generalization based on consistent experience or results: the law of supply and demand.
13. Mathematics A general principle or rule that is assumed or that has been proven to hold between expressions.
14. A principle of organization, procedure, or technique: the laws of grammar; the laws of visual perspective.
a law unto (oneself)
A totally independent operator: An executive who is a law unto herself.
take the law into (one's) own hands
To mete out justice as one sees fit without due recourse to law enforcement agencies or the courts.
[Middle English, from Old English lagu, from Old Norse *lagu, variant of lag, that which is laid down; see legh- in the Appendix of Indo-European roots.]