a transparent sheet with drawings, figures, etc. on it that can be placed on top of another sheet in order to change it 套图透明膜；上衬
() extra data from another organization that is added to a company's mailing list (= a list of the names and addresses of people who are regularly sent information or advertising material) 附加数据◆overlay data such as age, income or job 如年龄、收入或工作之类的附加数据