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

the rules of chess.

the code of regulations observed by a religious order or congregation

the Franciscan rule.

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

the rule rather than the exception.

control, government, or dominion

under the rule of a dictator.

tenure or conduct of reign or office

during the rule of George III.

a prescribed mathematical method for performing a calculation or solving a problem.

ruler ( def. 2 ) .

( initial capital letter ) Astronomy . the constellation Norma.

Printing . a thin, type-high strip of metal, for printing a solid or decorative line or lines.

Law .

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).

a legal principle.

a court order in a particular case.

rules, Penology . (formerly)

a fixed area in the neighborhood of certain prisons within which certain prisoners were allowed to live.

the freedom of such an area.

Obsolete . behavior.

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

to rule the empire with severity.

to decide or declare judicially or authoritatively; decree

The judge ruled that he should be exiled.

to mark with lines, esp. parallel straight lines, with the aid of a ruler or the like

to rule paper.

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

to rule lines on paper.

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

For centuries, England ruled the seas.

to exercise dominating power or influence; predominate.

to exercise authority, dominion, or sovereignty.

to make a formal decision or ruling, as on a point at law.

to be prevalent or current

Higher prices ruled throughout France.

rule out,

to prove to be unrelated or not for consideration; eliminate; exclude

to rule out the possibility of error.

to make impossible or impracticable

The rainstorm ruled out the holiday camping.

as a rule

generally; usually

He arrives at eleven o'clock, as a rule.

rule the roost. roost ( def. 6 ) .

verb

serve , submit , plead

noun

aphorism , apothegm , assize , axiom , basis , brocard , canon , chapter and verse * , command , commandment , criterion , decorum , decree , decretion , dictum , direction , edict , etiquette , formula , fundamental , gnome , guide , guideline , keynote , keystone , law , maxim , model , moral , no-no’s , order , ordinance , precedent , precept , prescription , propriety , regimen , regulation , ruling , statute , tenet , test , the book , the numbers , truism , administration , ascendancy , authority , control , domination , dominion , empire , government , influence , jurisdiction , power , regime , regnancy , reign , sovereignty , supremacy , sway , course , custom , habit , normalcy , normality , order of things , policy , practice , procedure , routine , dominance , mastery , governance , institute , dictate , prescript , rubric , commonplace , norm , ordinary , code , covenant , creed , discipline , dynasty , imperative , method , methodology , predomination , principle , protocol , regency , standard , technique , theorem , touchstone , yardstick

verb

administer , be in authority , be in driver’s seat , be in power , bridle , command , conduct , control , crack the whip , curb , decree , dictate , direct , dominate , domineer , guide , hold sway , hold the reins , keep under one’s thumb , lay down the law , lead , order , overrule , predominate , preponderate , preside , prevail , regulate , reign , restrain , rule the roost * , run , run the show , sit on top of , sway , take over , adjudge , adjudicate , conclude , deduce , determine , establish , figure , find , fix , gather , hold , infer , lay down , pass upon , postulate , prescribe , pronounce , resolve , settle , theorize , govern , tyrannize , arbitrate , decide , referee , umpire , authority , axiom , canon , course , criterion , custom , decision , direction , doctrine , dominion , edict , empire , enactment , formula , government , head , influence , judge , jurisdiction , law , leadership , manage , maxim , method , ordinance , policy , practice , precept , principle , procedure , regency , regime , regimen , regulation , standard , statute , tenet , way

phrasal verb

avert , forestall , forfend , obviate , preclude , stave off , ward , bar , count out , debar , eliminate , except , keep out , shut out