Hi,
I am a bit surprised that no one answered:
Global variable = A variable that effects the entire world (as opposed to local variable).....  is not limitted to a specific area / country / continent. 
Automatic variable = A variable that is an automatic result of something else.  One has no control of it, as something happend that veriable is an automatic result. 
Static variable = A variable that doesn't (or very slightly) change with time.  It is static in nature. 
Best regards,