cy·cle / ˈsīkəl/ • n. 1. a series of events that are regularly repeated in the same order: the boom and slump periods of a trade cycle. ∎  the period of time taken to complete a single sequence of such events: the cells are shed over a cycle of twenty-eight days. ∎  technical a recurring series of successive operations or states, as in the working of an internal combustion engine, or in the alternation of an electric current or a wave. ∎  Biol. a recurring series of events or metabolic processes in the lifetime of a plant or animal: the storks' breeding cycle. ∎  Biochem. a series of successive metabolic reactions in which one of the products is regenerated and reused. ∎  Ecol. the movement of a simple substance through the soil, rocks, water, atmosphere, and living organisms of the earth. See carbon cycle, nitrogen cycle. ∎  Comput. a single set of hardware operations, esp. that by which memory is accessed and an item is transferred to or from it, to the point at which the memory may be accessed again. ∎  Physics a cycle per second; one hertz.2. a complete set or series. ∎  a series of songs, stories, plays, or poems composed around a particular theme: Wagner's Ring Cycle.3. a bicycle or tricycle. ∎  [in sing.] a ride on a bicycle.• v. [intr.] 1. ride a bicycle: she cycled to work every day.2. move in or follow a regularly repeated sequence of events: economies cycle regularly between boom and slump.

cycle
1. (cycle time) An interval of time in which one set of events or phenomena is completed. It is usually the time required for one cycle of the memory system – the time between successive accesses – of a computer, and is sometimes considered to be a measure of computer power.

2. Any set of operations that is repeated regularly and in the same sequence. The operations may be subject to variations on each repetition.

3. (circuit) of a graph. A path that starts and ends at the same vertex. A cycle is said to be simple provided no edge appears more than once, and is elementary if no vertex (other than the start) appears more than once. See also Euler cycle, Hamiltonian cycle.

4. A permutation of a set that maps some subset T = {t₁, t₂, …, t_m}

of S in such a way that each t_i is mapped into t_i+1 (i = 1, 2,…, m–1) and t_m is mapped into t₁; the remaining elements of S are left unaltered by the permutation. Two cycles (u₁ u₂ …) and (v₁ v₂ …)

are disjoint provided the sets {u₁, u₂, …} and {v₁, v₂, …}

are disjoint. Every permutation of a set can be expressed uniquely as the composition of disjoint cycles.

cycle.
1. Name for series of items written to be perf. as a group and sometimes linked thematically either musically or by subject, esp. song-cycle (Ger. Liedercyclus). In opera the greatest cycle (4 operas) is Wagner's Der Ring des Nibelungen.

2. A complete vibration in mus. acoustics.

3. Any of systems of equal temperament in which tonal material is obtained by dividing octave into number of equal intervals.

cycle In physics, series of changes through which any system passes which brings it back to its original state. For example, alternating current starts from zero voltage, rises to a maximum, declines through zero to a minimum and rises again to zero. In the internal combustion engine, the two-stroke engine completes one cycle each downward plunge and return; the four-stroke cycle takes two such movements.

cycle recurrent period of years XIV (only occas. before XVII); recurrent succession of things XVII; series of poems, etc., relating to a central event or epoch XIX. — F. cycle or late L. cyclus — Gr. kúklos circle (see WHEEL).
So cyclic XVIII. — F. cyclique or L. cyclicus or Gr. kuklikós.