effectiveness

What it means

1. countableuncountableThe property of being effective, of achieving results.

   The effectiveness of the drug was well established.

2. countableuncountableThe capacity or potential for achieving results.

   The problem with these precedents is that the Security Council did not authorize intervention in Syria, and an intervention there will thus harm, not help, the Council’s credibility and effectiveness.

   2013 August 31, Jack L. Goldsmith, “What Happened to the Rule of Law?”, in The New York Times

3. countableuncountableThe degree to which something achieves results.

   He questioned the effectiveness of the treatment.

   1 more example

   United were having more possession but a sign of the effectiveness of Liverpool's defence was that it took the visitors 76 minutes to force Mignolet into serious action, when he dived to punch away a shot from substitute Nani.

   2013 September 1, Phil McNulty, “Liverpool 1-0 Man Utd”, in BBC Sport, archived from the original on 16 Jul 2018

In a sentence

The effectiveness of the drug was well established.

Where it comes from

1. Proto-Indo-European*h₁éǵʰ
2. Proto-Indo-European*h₁éǵʰs
3. Proto-Italic*eks
4. Latinex
5. Latinex-
6. Proto-Indo-European*dʰeh₁-
7. Proto-Indo-European*dʰeh₁k-
8. Proto-Indo-European*dʰh₁kyéti
9. Proto-Italic*θakjō
10. Proto-Italic*fakjō
11. Latinfaciō
12. Latinefficiō
13. Latineffectīvu
14. Frencheffectif
15. Englisheffective
16. Englisheffectiveness

From effective + -ness.