instalment
Concise Oxford English Dictionary © 2008 Oxford University Press:
instalment /ɪnˈstɔːlmənt/ (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’.
'instalment' also found in these Oxford entries:

