instalmentin·stal·ment /ɪnˈstɔːlmənt-ˈstɒːl-/ British EnglishBrE, installment American EnglishAmE noun [countableC]FINANCE one of a series of regular payments that are made until all of an agreed amount has been paidSome customers prefer to pay by instalments.
This would be the first installment of the $645 million in aid pledged to the region.