add-on

剑桥词典

a piece of equipment that can be connected to a computer to give it an extra use
（电脑）附加设备，附件
A printer is a useful add-on. 打印机是个很有用的电脑附加设备。

an extra part that is added , especially to an officially organized plan , system , agreement , etc.
（尤指正式计划、制度、协议等的）附加部分，附加项目
Legal expenses cover is often sold as an add-on to household insurance policies . 诉讼费用险经常作为家庭财产保险的附加险出售。 返回 add-on