WordReference Random House Learner's Dictionary of American English © 2026ef•fec•tive /ɪˈfɛktɪv/USA pronunciation
adj.
- able to accomplish a purpose:very effective teaching methods.
- in operation or in force;
functioning: The law becomes effective at midnight.
- real;
actual;
in fact but not in theory:[before a noun]The militia was the effective government at the time.
- producing a deep or strong impression;
striking: an effective photograph.
ef•fec•tive•ly, adv.
ef•fec•tive•ness, n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2026ef•fec•tive
(i fek′tiv),USA pronunciation adj.
- adequate to accomplish a purpose;
producing the intended or expected result:effective teaching methods; effective steps toward peace.
- actually in operation or in force;
functioning:The law becomes effective at midnight.
- producing a deep or vivid impression;
striking:an effective photograph.
- Militaryprepared and available for service, esp. military service.
n.
- Militarya member of the armed forces fit for duty or active service.
- Militarythe effective total of a military force.
- Latin effectīvus practical, equivalent. to effect(us), past participle of efficere (see effect) + -īvus -ive
- Middle English 1350–1400
1. capable, competent. Effective, effectual, efficacious, efficient refer to that which is able to produce a (desired) effect. Effective is applied to that which has the power to, or which actually does, produce an effect:an effective action, remedy, speech.Effectual is used esp. of that which produces the effect desired or intended, or a decisive result:An effectual bombardment silenced the enemy.Efficacious suggests the capability of achieving a certain end:an efficacious plan, medicine.Efficient (applied also to persons) implies the skillful use of energy or industry to accomplish desired results with little waste of effort:efficient methods; an efficient manager. 2. operative. 3. telling.
Collins Concise English Dictionary © HarperCollins Publishers::
effective /ɪˈfɛktɪv/ adj - productive of or capable of producing a result
- in effect; operative
- producing a striking impression; impressive: an effective entrance
- (prenominal) actual rather than theoretical; real
- (of a military force, etc) equipped and prepared for action
- (of an alternating quantity) having a value that is the square root of the mean of the squares of the magnitude measured at each instant over a defined period of time, usually one cycle
See also root mean square
n - a serviceman who is equipped and prepared for action
efˈfectively adv efˈfectiveness, effectivity /ɪˌfɛkˈtɪvɪtɪ/ n
'effectivity' also found in these entries (note: many are not synonyms or translations):
