Prerequisite

a.	1.	Previously required; necessary as a preliminary to any proposed effect or end; as, prerequisite conditions of success.
n.	1.	Something previously required, or necessary to an end or effect proposed. The necessary prerequisites of freedom. - Goldsmith.

Noun	1.	prerequisite - something that is required in advance; "Latin was a prerequisite for admission" Synonyms: requirement
Adj.	1.	prerequisite - required as a prior condition or course of study

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