What does "clonic" mean in relation to epilepsy?

What does "clonic" mean in relation to epilepsy?

Charles Ribak, Ph.D. (Professor of Anatomy and Neurobiology, UC Irvine School of Medicine) gives expert video advice on: What is a "photosensitivity" seizure trigger?; What is an "automatism"? and more...

With epilepsy, clonic refers to another type of movement of the arms and legs where we often have very rapid flexion. For example, for the arm, the largest flexor muscle is the bicep. A clonic movement for this would be a flexing movement of the arm. This is in contrast to the term "tonic" where we would have an extension of the arm.