(~s)
Note: in AM, use 'installment'
1.
If you pay for something in ~s, you pay small sums of money at regular intervals over a period of time, rather than paying the whole amount at once.
The first ~ of ?1 per share is payable on application.
N-COUNT
2.
An ~ of a story or plan is one of its parts that are published or carried out separately one after the other.
...the disappointing third ~ of the Highlander series.
= part
N-COUNT