What is the differences between novae and supernovae?

Nova comes from the Latin which means "new star" and is associated with a sudden brightening of a star and then gradually returns to its original form over a period that may vary from weeks to years.

While Supernova is infrequent celestial phenomena associated with the explosion of the material of star which results in a bright short-lived entity that emits a large amount of energy.

Supernova destroys its host star while nova does not destroy its host star and results in only a small amount of mass destruction.