ef·fec·tive | \ i-ˈfek-tiv , e-, ē-, ə-
Essential Meaning of effective
1: producing a result that is wanted : having an intended effect
drugs effective in the treatment of a disease = drugs effective in treating a disease = drugs effective against a disease
It’s a simple but effective technique.
He gave an effective speech.
2; of a law, rule, etc. : in use : ACTIVE
The law becomes effective [=the law takes effect; the law will start to be used] next year.
the effective date of the law [=the day when the law starts to be used]
3: starting at a particular time