Formerly known as "Document Objects" (DocObjects), ActiveX Documents are extensions to Microsoft's OLE compound document architecture that allow a container application to use the full capabilities of server applications.

Containers Launch Servers
As of Version 3.0, Internet Explorer (IE) was made an ActiveX Documents "container." Microsoft Office applications and the HTML viewer used to render Web pages are ActiveX Document "servers." Thus, IE can view a Web page, an Excel spreadsheet or a Word document by launching the appropriate server application.