Software to tell what a key on my keyboard is referencing?

[gizmo1990]

I've got a key on my keyboard labled FN. I'd like to know what this is referencing so I can use autohotkey to retag it to something else.
Does anyone know of a program which will tell me what the key is referencing? Or knows of some way in windows to find out?

 

[True_Scotsman]

Its a function key, usualy blue or orange text, that will allow use of other keys (media and special fuction keys) generally above the number keys (or on them).

What keyboard is it?

 

[PatZ1989]

Generally FN key is on laptops, is it writen in a different colour?