(1) A tool that combines two or more files into a single file, usually for the purpose of hiding one of them. Commonly associated with Trojan horses, where the Trojan is bound to a real file, such as a text file that opens with Notepad or other program. The users believe they are opening a safe file, and that is what appears on the screen, but at the same time the file is running, the Trojan is also running, usually undetected by the user.
(2) Same as linker.