Ever since the release of Vim version 7.0, there has been support for tabs or tab pages as it is called. Tab pages are not like the normal tabs in other applications; rather they are a way to group your open files. Each tab can contain several open buffers and even several windows at the same time.
What makes tabs special is the commands that you would normally execute on all open buffers / windows (such as
:bufdo, :windo, :all, and
:ball) are limited to only the windows and buffers in the current tab page.
Normally, tab pages are shown as a list of tabs at the top of the window (just above the editing area). Each tab has a label, which by default shows the name of the file in the currently active buffer. If more windows are open ...