English edit

Alternative forms edit

Etymology edit

From French effectif, from Latin effectīvus (productive; effective), from efficiō (I make; I bring about).

Pronunciation edit

Adjective edit

effective (comparative more effective, superlative most effective)

  1. Having the power to produce a required effect or effects.
    Synonym: efficacious
    The pill is an effective method of birth control.
  2. Producing a decided or decisive effect.
    The president delivered an effective speech!
    • 1651, Jer[emy] Taylor, The Rule and Exercises of Holy Living. [], 2nd edition, London: [] Francis Ashe [], →OCLC:
      Whosoever is an effective, real cause of doing his neighbour wrong, is criminal.
  3. Efficient, serviceable, or operative, available for useful work.
    Antonym: nominal
    How long does it take to make a bunch of civilians an effective military force?
    My effective income after taxes and child support is $500 a month.
    The effective radiated power is determined by multiplying the transmitter power output with the antenna gain.
    The effective voltage of an alternating current is 0.7 times its peak voltage.
  4. Actually in effect.
    The curfew is effective at midnight.
  5. (geometry, of a cycle or divisor) Having no negative coefficients.
  6. (physics, for any effective theory) approximate; Not describing the fundamental dynamic changes in some system as they happen.

Usage notes edit

Webster's Revised Unabridged Dictionary from 1913 lists efficient and effective as synonyms, but all major dictionaries now show that these words now only have different meanings in careful use. Use of both for the other meaning is however widespread enough that Longman's Exam Dictionary, for example, finds it necessary to proscribe the use of one for the other with several examples at each entry and provides the following summary:

  • efficient = working quickly and without waste
  • effective = having the desired effect

Derived terms edit

Related terms edit

Translations edit

The translations below need to be checked and inserted above into the appropriate translation tables. See instructions at Wiktionary:Entry layout § Translations.

Noun edit

effective (plural effectives)

  1. (military) a soldier fit for duty

French edit

Pronunciation edit

Adjective edit


  1. feminine singular of effectif

Latin edit

Adjective edit


  1. vocative masculine singular of effectīvus