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.
prepared and available for service, especially military service.


a member of the armed forces fit for duty or active service.
the effective total of a military force.

Nearby words

  1. effable,
  2. efface,
  3. effect,
  4. effected,
  5. effecter,
  6. effective conjugate,
  7. effective current,
  8. effective dose,
  9. effective half-life,
  10. effective osmotic pressure

Origin of effective

1350–1400; Middle English < Latin effectīvus practical, equivalent to effect(us), past participle of efficere (see effect) + -īvus -ive

SYNONYMS FOR effective
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 especially 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.

Related forms
Can be confusedaffective effective (see synonym study at the current entry)

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for effective

British Dictionary definitions for effective



productive of or capable of producing a result
in effect; operativeeffective from midnight
producing a striking impression; impressivean effective entrance
(prenominal) actual rather than theoretical; realthe effective income after deductions
(of a military force, etc) equipped and prepared for action
physics (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 cycleSee also root mean square


a serviceman who is equipped and prepared for action
Derived Formseffectively, adverbeffectiveness, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for effective



late 14c., from French effectif, from Latin effectivus "productive, effective," from effect-, stem of efficere (see effect (n.)). Effectively in the sense of "actually" is attested by 1650s. Related: Effectivity.

Online Etymology Dictionary, © 2010 Douglas Harper