The cyclic nature of the seasons is something we can always rely on.
Relating to a cycle or cycles, especially in chemistry, where it refers to compounds with a ring of atoms.
Benzene is a cyclic compound with a ring structure of carbon atoms.
Mathematics, Geometry: Forming or relating to a closed circle or loop; especially (of a group) generated by a single element, or (of a polygon) having all vertices on a common circle.
In group theory, the integers under addition constitute a cyclic group.