Maxflyer: Alt means alternative, as an example on older DOS based programs such as the original MS Word you could use Alt and F to open the file menu.
And indeed you still can with most Windows programs. If you see a menu or command item with an underlined letter in it (eg
File or F
avorites), you can usually access that menu by pressing Alt and then the underlined letter, eg Alt-F or Alt-A.
Very useful for those of us who find keyboard commands much much faster than mousing.