Are epilepsy and fits the same thing?

American actor Cameron Boyce, best known for his starring role in the Descendants tv movies, recently died in his sleep following a seizure that was caused by epilepsy. — AFP

I recently read about the case of a young actor dying of epilepsy. Then I read about a young athlete collapsing after exercise and dying because of epilepsy. What is epilepsy?

Epilepsy is a neurological disorder characterised by fits or seizures, or even periods of unusual behaviour, sensations or loss of awareness. Fits happen when the nerve cells in your brain either misfire or repetitively fire.