from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Power or capacity to produce a desired effect; effectiveness.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Ability to produce a desired amount of a desired effect.
from the GNU version of the Collaborative International Dictionary of English
- n. Power to produce effects; operation or energy of an agent or force; production of the effect intended
from The Century Dictionary and Cyclopedia
- n. The quality of being efficacious or effectual; production of, or the capacity of producing, the effect intended or desired; effectiveness.
- n. Synonyms Efficiency, etc. (see effectiveness); virtue, force, energy.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. capacity or power to produce a desired effect
Latin efficācia, from efficāx, efficāc-, efficacious; see efficacious.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin efficacia ("efficacy"), from efficax ("efficacious"); see efficacious. (Wiktionary)