Cyklus

Cyklus is a term used in several languages to refer to a sequence of events or states that recurs in a predictable manner, forming a cycle. Cycles can be periodic or quasi-periodic and may vary in duration from seconds to years. The concept appears across natural and human-made systems.

Etymology and usage: The word derives from Latin cyclus, from Greek kyklos, meaning circle or wheel. In Czech and Slovak, cyklus is the standard spelling; in Polish the form cykl is more common; in English the equivalent is cycle. The term is often qualified by a field, such as the circadian cycle or the life cycle.

Applications: In biology, the cell cycle governs cell division; circadian and menstrual cycles regulate timing of physiological processes. In the environment, cycles include the water cycle and carbon cycle. In technology, the four-stroke engine cycle or refrigeration cycle describe a repeating sequence of processes; in business, the economic or business cycle describes fluctuations in economic activity. In mathematics and computer science, cycles refer to closed paths in graphs, cyclic groups, and periodic signals. The concept also appears in literature and art as a cycle of works or a cycle of stories.

See also: periodicity, loop, cycle length, cycle detection.