Meaning of EFFECTIVE in English

EFFECTIVE

/ ɪˈfektɪv; NAmE / adjective

1.

producing the result that is wanted or intended; producing a successful result :

Long prison sentences can be a very effective deterrent for offenders.

Aspirin is a simple but highly effective treatment.

drugs that are effective against cancer

I admire the effective use of colour in her paintings.

OPP ineffective

—see also cost-effective

2.

[ only before noun ] in reality, although not officially intended :

the effective, if not the actual, leader of the party

He has now taken effective control of the country.

3.

( formal ) ( of laws and rules ) coming into use :

The new speed limit on this road becomes effective from 1 June.

►  ef·fect·ive·ness (also less frequent ef·fect·iv·ity / ɪˌfekˈtɪvɪti; NAmE /) noun [ U ]:

to check the effectiveness of the security system

••

WORD ORIGIN

late Middle English : from Latin effectivus , from efficere accomplish, from ex- out, thoroughly + facere do, make.

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.