Look up cycle, cyclic, or cyclical in Wiktionary, the free dictionary. Cycle, cycles, or cyclic may refer to: Cyclic history, a theory of history Cyclical...

The water cycle (or hydrologic cycle or hydrological cycle) is a biogeochemical cycle that involves the continuous movement of water on, above and below...

The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system...

The solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a nearly periodic 11-year change in the Sun's activity...

The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). Animals that use...

Look up life cycle in Wiktionary, the free dictionary. Life cycle, life-cycle, or lifecycle may refer to: Biological life cycle, the sequence of life stages...

The carbon cycle is that part of the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere...

The sexagenary cycle, also known as the ganzhi or stems-and-branches is a cycle of sixty terms, each corresponding to one year, thus a total of sixty years...

The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle, or TCA cycle (tricarboxylic acid cycle)—is a series of biochemical reactions...

The cell cycle, or cell-division cycle, is the sequential series of events that take place in a cell that causes it to divide into two daughter cells...