The property of being effective, of achieving results. / The capacity or potential for achieving results. / The degree to which something achieves results.

plural of effectiveness

The result or outcome of a cause. / Impression left on the mind; sensation produced. / Execution; performance; realization; operation.

(transitive) To make or bring about; to implement. / Misspelling of affect

In an efficient or effective manner; with powerful effect. / Essentially, in effect, for all practical purposes.

Operating or functioning; in force; in play.

For all practical purposes; in practice; actually; essentially; basically.

(uncountable) The ability or power to be effective. / (countable) A measure of the effectiveness of something.

simple past tense and past participle of effect

(music) Modified by effects.