rule (ro?ol)n.1. a. Governing power or its possession or use; authority.b. The duration of such power.2. a. An authoritative, prescribed direction for conduct, especially one of the regulations governing procedure in a legislative body or a regulation observed by the players in a game, sport, or contest.b. The body of regulations prescribed by the founder of a religious order for governing the conduct of its members.3. A usual, customary, or generalized course of action or behavior: “The rule of life in the defense bar ordinarily is to go along and get along” (Scott Turow).4. A generalized statement that describes what is true in most or all cases: In this office, hard work is the rule, not the exception.5. Mathematics A standard method or procedure for solving a class of problems.6. Law a. A court decision serving as a precedent for subsequent cases: the Miranda rule.b. A legal doctrine or principle.c. A court order.d. A minor regulation or law.e. A statute or regulation governing the court process: rule of procedure; rule of evidence.7. See ruler.8. Printing A thin metal strip of various widths and designs, used to print borders or lines, as between columns.v. ruled, rul·ing, rules v.tr.1. To exercise control, dominion, or direction over; govern: rule a kingdom.2. a. To have a powerful influence over; dominate: “Many found the lanky westerner naive, and supposed that he would be ruled by one of his more commanding cabinet officers” (William Marvel).b. To be a preeminent or dominant factor in: “It was a place where … middle-class life was ruled by a hankering for all things foreign” (Amitav Ghosh).3. To decide or declare authoritatively or judicially; decree: The judges ruled that the answer was acceptable. The police ruled the death a homicide. The law was ruled unconstitutional. See Synonyms at decide.4. a. To mark with straight parallel lines.b. To mark (a straight line), as with a ruler.v.intr.1. To be in total control or command; exercise supreme authority.2. To formulate and issue a decree or decision.3. To prevail at a particular level or rate: Prices ruled low.4. Slang To be excellent or superior: That new video game rules!Phrasal Verb: rule out1. To prevent; preclude: The snowstorm ruled out their weekly meeting.2. To remove from consideration; exclude: The option of starting over has been ruled out.Idiom: as a rule In general; for the most part: As a rule, we take the bus.[Middle English reule, from Old French, from Vulgar Latin *regula, from Latin r?gula, rod, principle; see reg- in Indo-European roots.]rul?a·ble adj.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.rule (ru?l) n1. an authoritative regulation or direction concerning method or procedure, as for a court of law, legislative body, game, or other human institution or activity: judges’ rules; play according to the rules. 2. (Government, Politics & Diplomacy) the exercise of governmental authority or control: the rule of Caesar. 3. (Government, Politics & Diplomacy) the period of time in which a monarch or government has power: his rule lasted 100 days. 4. a customary form or procedure; regular course of action: he made a morning swim his rule. 5. the rule the common order of things; normal condition: violence was the rule rather than the exception. 6. (Mathematics) a prescribed method or procedure for solving a mathematical problem, or one constituting part of a computer program, usually expressed in an appropriate formalism7. (Computer Science) a prescribed method or procedure for solving a mathematical problem, or one constituting part of a computer program, usually expressed in an appropriate formalism8. (Grammar) a formal expression of a grammatical regularity in a linguistic description of a language9. (Tools) any of various devices with a straight edge for guiding or measuring; ruler: a carpenter’s rule. 10. (Printing, Lithography & Bookbinding) a. a printed or drawn character in the form of a long thin lineb. another name for dash113: en rule; em rule. c. a strip of brass or other metal used to print such a line11. (Ecclesiastical Terms) Christianity a systematic body of prescriptions defining the way of life to be followed by members of a religious order12. (Law) law an order by a court or judge13. as a rule normally or ordinarilyvb14. (Government, Politics & Diplomacy) to exercise governing or controlling authority over (a people, political unit, individual, etc): he ruled for 20 years; his passion for her ruled his life. 15. (when tr, often takes a clause as object) to decide authoritatively; decree: the chairman ruled against the proposal. 16. (tr) to mark with straight parallel lines or make one straight line, as with a ruler: to rule a margin. 17. (tr) to restrain or control: to rule one’s temper. 18. (intr) to be customary or prevalent: chaos rules in this school. 19. (intr) to be pre-eminent or superior: football rules in the field of sport. 20. (Astrology) (tr) astrology (of a planet) to have a strong affinity with certain human attributes, activities, etc, associated with (one or sometimes two signs of the zodiac): Mars rules Aries. 21. rule the roost rule the roast to be pre-eminent; be in charge[C13: from Old French riule, from Latin r?gula a straight edge; see regulate] ?rulable adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014rule (rul) n., v. ruled, rul?ing. n. 1. a principle or regulation governing conduct, procedure, arrangement, etc. 2. the customary or normal circumstance, occurrence, practice, quality, etc.: the rule rather than the exception. 3. control, government, or dominion. 4. tenure or conduct of reign or office. 5. the code of regulations observed by a religious order or congregation. 6. a prescribed mathematical method for performing a calculation or solving a problem. 7. ruler (def. 2). 8. a solid or decorative line, as used for separating newspaper columns. 9. a. a formal order made by a law court, esp. for governing the procedure of the court. b. a legal principle. c. a court order in a particular case. 10. Obs. behavior. v.t. 11. to exercise dominating power, authority, or influence over; govern: to rule a kingdom. 12. to decide or declare judicially or authoritatively; decree. 13. to mark with lines, esp. parallel straight lines, with the aid of a ruler or the like: to rule paper. 14. to mark out or form (a line) by this method. 15. to be superior or preeminent in (a field or group); hold sway over. v.i. 16. to exercise dominating power or influence; predominate. 17. to exercise authority, dominion, or sovereignty. 18. to make a formal decision or ruling, as on a point at law. 19. to be prevalent or current. 20. Slang. to be especially popular, preeminent, or superlative: The Yankees rule! 21. rule out, to eliminate from consideration. Idioms: as a rule, generally; usually. [1175?1225; (n.) Middle English riule, reule