What is a maxis dress?

i understand maxis dresses are very populars right now and everyone keeps chatting about them but i dont get what they are... is it a dress that you can wear a super maxi pad with that wont squeek or show through like a cameled toe? I have always had a problem with my maxi pads showing through my clothings or making noises.. and where can i find these "maxi pad" dressings?