Where to find an explanation of what pin names mean?

Hi folks! I'm new to playing with microcontrollers and jumping in with both feet. Does anyone have a link to a glossary of microcontroller terms and shorthand, or some similar resource?

Right now, I'm working on building a game controller and trying to find out what all of the pin names on an ATMega32u4 refer to, specifically the difference in the use of the Vcc, UVcc, and Vbus pins. I could just ask a million individual questions, but I'm wondering if someone's made a comprehensive glossary of all of the shorthand and abbreviations. Thanks!

Have you looked at the datasheet yet?
http://www.microchip.com/wwwproducts/en/atmega32u4