The ability or power to be effective.
[Technical documentation] An indication of the product, procedure, or timescale for which an item of information is applicable or effective.
A measure of the effectiveness of something.
Power, authority to do something.
A legal obligation on a government to make payments to a person, business, or unit of government that meets the criteria set in law, such as social security in the US.
The right to have something, whether actual or perceived.
Something that one is entitled to.