Some people say marykate and ashley have bags under their eyes (when they were littler)
What does that mean to have bags under your eyes? I hope this isn't a dumb question.

When you don't sleep.... the dark circle under your eyes are called bags.

Go to the thread farther down entitled "Did anyone notice this?!"
Look at the pictures of the twins. They have puffy little sacks under their eyes. Those are the bags. They were very young to have those.