Conversation Between Rapid Roy and Drillbit

This is a newb question so you will have to excuse me I am new to RC cars. You posted a reply to a question of mine on the micro rs4 thread and as far as batteries you said 6 cell 2/3 A pack. I have no idea what that means if you could explain it that would be awesome. Sorry for the newb question but I want to be able to know what I am talking aboutwhen i go go to get parts for this thing. Thanks