Is a combo the same as a meal?

Excuse me, could you please clarify something for me? I've been wondering about the difference between a combo and a meal. I've seen both terms used on menus and in fast food restaurants, but I'm not sure if they mean the same thing. Is a combo simply a meal that comes with a few extra items, like a side or a drink, or is there a more distinct difference between the two? Could you please explain the distinction, if any, to me?