cyclicly

Pel-Ebstein fever is a rarely seen condition noted in patients with Hodgkin's lymphoma in which the patient experiences fevers which cyclicly increase then decrease over an average period of one or two weeks.

"Electromagnetic energy is energy which is cyclicly transformed from an electric field to a magnetic field and back again, and possesses the property of traveling as radiation through space at a speed of a hundred and eighty-six thousand miles per second.