rule

1. a principle or regulation governing conduct, action, procedure, arrangement, etc.:

   the rules of chess.

   Synonyms: standard, guideline, precept, order, dictate, decree, regulation, law, bylaw

2. the code of regulations observed by a religious order or congregation:

   the Franciscan rule.

3. the customary or normal circumstance, occurrence, manner, practice, quality, etc.:

   the rule rather than the exception.

4. control, government, or dominion:

   under the rule of a dictator.

   Synonyms: tyranny, oppression, mastery, domination, regulation, management, government, direction, sway, power, dominion, command, authority

5. tenure or conduct of reign or office:

   during the rule of George III.

6. a prescribed mathematical method for performing a calculation or solving a problem.
7. ruler ( def 2 ).
8. Rule, Astronomy. the constellation Norma.
9. Printing. a thin, type-high strip of metal, for printing a solid or decorative line or lines.
10. Law.
    1. a formal order or direction made by a court, as for governing the procedure of the court general rule or for sending the case before a referee special rule.
    2. a legal principle.
    3. a court order in a particular case.
11. rules, Penology. (formerly)
    1. a fixed area in the neighborhood of certain prisons within which certain prisoners were allowed to live.
    2. the freedom of such an area.
12. Obsolete. behavior.

1. to control or direct; exercise dominating power, authority, or influence over; govern:

   to rule the empire with severity.

2. to decide or declare judicially or authoritatively; decree:

   The judge ruled that he should be exiled.

   Synonyms: judge, dictate

3. to mark with lines, especially parallel straight lines, with the aid of a ruler or the like:

   to rule paper.

4. to mark out or form (a line) by this method:

   to rule lines on paper.

5. to be superior or preeminent in (a specific field or group); dominate by superiority; hold sway over:

   For centuries, England ruled the seas.

1. to exercise dominating power or influence; predominate.
2. to exercise authority, dominion, or sovereignty.
3. to make a formal decision or ruling, as on a point at law.
4. to be prevalent or current:

   Higher prices ruled throughout France.

verb phrase

1. 1. to prove to be unrelated or not for consideration; eliminate; exclude:

      to rule out the possibility of error.

   2. to make impossible or impracticable:

      The rainstorm ruled out the holiday camping.