What does a document mean?

Answer 1

"Bat" is short for "batch" which is a type of scripting language for computers. They're basically just text files which you can write to do simple tasks for you. To read one (on Windows) right-click the file, then choose "open with" and select Notepad.

Further reading: http://en.wikipedia.org/wiki/.bat A batch file is a text file that contains a sequence of commands for a computer operating system. It's called a batch file because it batches (bundles or packages) into a single file a set of commands that would otherwise have to be presented to the system interactively from a keyboard one at a time. A batch file is usually created for command sequences for which a user has a repeated need. Commonly needed batch files are often delivered as part of an operating system. You initiate the sequence of commands in the batch file by simply entering the name of the batch file on a command line.