Definition of requirement:
essential, extremity, urgency, necessary, want, obsession, engrossment, exigency, prepossession, lack, demand, requisition, pinch, call, desideratum, fatality, qualification, preoccupation, stress, destiny, indispensability, element, necessity, terms, reservation, prerequisite, basis, fate, precondition, sine qua non, indispensableness, fundamental, exaction, claim, provision, emergency, requisite, specification, unavoidableness.
- obligation (part of speech: noun)
- requirement (part of speech: noun)
- "The Framework of Home Rule", Erskine Childers.
- "The Book of Household Management", Mrs. Isabella Beeton.
- "The Prospective Mother A Handbook for Women During Pregnancy", J. Morris Slemons.