What are these things called Matchbooks?

After stumbling across these adorable Matchbooks on Cute Overload, I knew what my next art project was going to be... Matchbooks you say? Apparently Belinda had a hard time figuring out these devices, as it took me a good 10 minutes to try and explain it before she googled it instead.

Punkity

Happy Matchsticks

Ballerina Pink

Inspire Greatness

Preppy Kitty

A Sparkly Gift

Happiness