Let's say you have to pay an amount, and you can pay it in separate parts, what's the word to describe that? I'm sure there's a right word for this but I just can't put my fingers on it.
The phrase is "pay in installments". ("instalments" in British English)
The definition is:
a sum of money due as one of several equal payments for something, spread over an agreed period of time.
Usage of "installments" in sentences:
We agreed to pay for the car by/in installments.
Alternatively, in British English, it can also be termed as "hire purchase".
a system by which one pays for a thing in regular instalments while having the use of it.