What is a Compound Word?

As I am typing, the kids are supposed to be cleaning the playroom. This is all I hear:

Emma: “No it’s NOT!”

Paige: “Yes it IS!”

Avery: “Uh huh!”

I stormed in. “Why aren’t you picking up your toys!?” Emma answered, “Mom! Paige said that ‘clean up’ is a compound word!” To which Paige argued, “It is! It is!”

So there you have it-my kids are so smart they argue about what is compound and what is not… while cleaning their playroom.