requirement -
anything indispensable; "food and shelter are necessities of life"; "the essentials of the good life"; "allow farmers to buy their requirements under favorable conditions"; "a place where the requisites of water fuel and fodder can be obtained"
requirement -
A statement in domain specific terms which specifies a verifiable constraint on an implementation that it shall undeniably meet or a be deemed unacceptable, or b result in implementation failure, or c result in system failure.
Wikipedia
A requirement is a singular documented need of what a particular product or service should be or perform. It is most commonly used in a formal sense in systems engineering or software engineering. It is a statement that identifies a necessary attribute, capability, characteristic, or quality of a system in order for it to have value and utility to a user.
OmegaWiki Dictionary
Ω
requirement In engineering, a singular documented need of what a particular product or service should be or do.
requirement Indispensable circumstance that makes possible a specific condition.