instalment
/ɪnˈstɔːlmənt/( <美> 亦作installment)
noun
1
- a sum of money due as one of several equal payments for something, spread over an agreed period of time（分期付款的）一期付款：
the first instalment of a grant for housing
第一期住房补贴
the purchase price is paid in instalments.
以分期付款支付购买价。
2
- any of several parts of something which are published, broadcast, or made public in sequence at intervals（出版、播放或发表的任何一个）分期（部分）：
filming the final instalment in his Vietnam trilogy.
摄制他的越南三部曲的最后几集。
3
- mass noun the process of installing something; installation安装, 安置：
instalment will begin early next year.
将于明年初开始安装。
词源
mid 18th cent. (denoting the arrangement of payment by instalments)： alteration of obsolete estalment （probably by association with INSTALLATION）, from Anglo-Norman French estalement, from Old French estaler 'to fix'.