The word "nova" is Latin for new. The words "Nova" and "Supernova" were assigned by ancient astronomers who, when they looked up in a sky, saw a new bright star, and called it a nova, or new. An even brighter star was a supernova. Then names stuck, and even though novae and supernovae are not related (except for the fact that the stars get brighter) the terms are still used today.