Epilepsy is a tendency to have repeated seizures.
Many patients have a seizure only once in their lifetime. They do not get seizures repeatedly. These patients do not have epilepsy.
Many patients who have a single seizure do not develop Epilepsy.
However, some patients keep on having seizures. They have a higher tendency to have seizures. This is called epilepsy. Some of them have a clear reason for this tendency such as a stroke, a tumor or some problem in the development of the brain. In other people, the reason is not clear.
A doctor usually gets MRI and EEG done if a patient has a seizure. This is to find if you have a tendency to have repeated seizures. If you do have a higher tendency, then we can say that you have “Epilepsy”.