requirement

(noun) required activity. Synonyms: demand. Examples: "The requirements of his work affected his health." "There were many demands on his time."

(noun) anything indispensable. Synonyms: necessity, essential, requisite, necessary. Examples: "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."

(noun) something that is required in advance. Synonyms: prerequisite. Example: "Latin was a prerequisite for admission."