cycle
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.