( US also installment )
■ noun
1》 a sum of money due as one of several equal payments for something, spread over an agreed period of time.
2》 one of several parts of something which are published or broadcast in sequence at intervals.
Origin
C18: alt. of obs. estalment (prob. by assoc. with installation ), from Anglo-Norman Fr. estalement , from OFr. estaler 'to fix'.