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...

mountain bike racing, track cycling, BMX, and cycle speedway. Non-racing cycling sports include artistic cycling, cycle polo, freestyle BMX, mountain...

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

A Yuga Cycle (a.k.a. chatur yuga, maha yuga, etc.) is a cyclic age (epoch) in Hindu cosmology. Each cycle lasts for 4,320,000 years (12,000 divine years)...

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

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...

The estrous cycle (from Latin oestrus 'frenzy', originally from Ancient Greek οἶστρος (oîstros) 'gadfly') is a set of recurring physiological changes...

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 stems-and-branches or ganzhi (Chinese: 干支), is a cycle of sixty terms, each corresponding to one year, thus a...

beats per minute, each cardiac cycle, or heartbeat, takes about 0.8 second to complete the cycle. Duration of the cardiac cycle is inversely proportional to...

The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial...

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...

Cycling, also known as bicycling or biking, is the activity of riding a bicycle or other type of cycle. It encompasses the use of human-powered vehicles...

The Calvin cycle, light-independent reactions, bio synthetic phase, dark reactions, or photosynthetic carbon reduction (PCR) cycle of photosynthesis is...

biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is transformed and cycled by...

The Hainish Cycle consists of a number of science fiction novels and stories by Ursula K. Le Guin. It is set in a future history in which civilizations...

The instruction cycle (also known as the fetch–decode–execute cycle, or simply the fetch-execute cycle) is the cycle that the central processing unit (CPU)...

The Brayton cycle, also known as the Joule cycle, is a thermodynamic cycle that describes the operation of certain heat engines that have air or some other...

A diurnal cycle (or diel cycle) is any pattern that recurs every 24 hours as a result of one full rotation of the planet Earth around its axis. Earth's...

The cycle rickshaw is a small-scale local means of transport. It is a type of hatchback tricycle designed to carry passengers on a for-hire basis. It...

Otto cycle is an idealized thermodynamic cycle that describes the functioning of a typical spark ignition piston engine. It is the thermodynamic cycle most...

The CNO cycle (for carbon–nitrogen–oxygen; sometimes called Bethe–Weizsäcker cycle after Hans Albrecht Bethe and Carl Friedrich von Weizsäcker) is one...

The Atkinson-cycle engine is a type of internal combustion engine invented by James Atkinson in 1882. The Atkinson cycle is designed to provide efficiency...

The Fenian Cycle (/ˈfiːniən/), Fianna Cycle or Finn Cycle (Irish: an Fhiannaíocht) is a body of early Irish literature focusing on the exploits of the...

A thermodynamic cycle consists of linked sequences of thermodynamic processes that involve transfer of heat and work into and out of the system, while...

The Ulster Cycle (Irish: an Rúraíocht), formerly known as the Red Branch Cycle, is a body of medieval Irish heroic legends and sagas of the Ulaid. It...

The rock cycle is a basic concept in geology that describes transitions through geologic time among the three main rock types: sedimentary, metamorphic...