add-on
add-on
'add-on
◙noun [C]
1. something extra that is added to an existing plan, agreement, law etc
• 〔现存计划、协议、法律等的〕补充:
▪ [+to]
»We bought legal protection as an add-on to our home insurance policy.
我们购买了法律保障险，作为家庭财产保单的补充。
2. a piece of equipment that you connect to a computer to improve its performance
• 〔计算机的〕附加设备，附件:
»an add-on circuit board
一块附加电路板
3. a product that is designed to be used with another product
• 附加装置
