Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “effective”

effective

adjective uk   /ɪˈfek.tɪv/ us  

effective adjective (SUCCESSFUL)

B2 successful or achieving the results that you want: It's an extremely effective cure for a headache. The lighting for the production made a very effective use of shadow. She's a very effective teacher.
Opposite

effective adjective (IN FACT)

[before noun] in fact, although not officially: Although she's not officially our boss, she's in effective control of the office.

effective adjective (IN USE)

If a law or rule becomes effective, it starts to be used: The new laws will become effective next month.
effectiveness
noun [U] uk   /-nəs/ us  
C1 There are doubts about the effectiveness of the new drug (= how successful it is) in treating the disease.
(Definition of effective from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of effective?
Add Cambridge dictionaries to your browser to your website

More meanings of “effective”

Definitions of “effective” in other dictionaries

Word of the Day

dawn on sb

If a fact dawns on you, you understand it after a period of not understanding it.

Word of the Day

The language of work

by Kate Woodford,
October 15, 2014
Most of us talk about our jobs. We tell our family and friends interesting or funny things that have happened in the workplace (=room where we do our job), we describe – and sometimes complain about – our bosses and colleagues and when we meet someone for the first time, we tell

Read More 

life tracking noun

October 20, 2014
the use of one or more devices or apps to monitor health, exercise, how time is spent, etc.

Read More