Definitions
1.nounA regulation, law, guideline."All participants must adhere to the rules."
2.nounA ruler; device for measuring, a straightedge, a measure.
3.nounA straight line (continuous mark, as made by a pen or the like), especially one lying across a paper as a guide for writing.
4.nounA regulating principle.
5.nounThe act of ruling; administration of law; government; empire; authority; control.
6.nounA normal condition or state of affairs."As a rule, our senior editors are serious-minded."
7.nounConduct; behaviour.
8.nounAn order regulating the practice of the courts, or an order made between parties to an action or a suit.
9.nounA determinate method prescribed for performing any operation and producing a certain result."a rule for extracting the cube root"
10.nounA thin plate of brass or other metal, of the same height as the type, and used for printing lines, as between columns on the same page, or in tabular work.