n. - An imaginary circle or orbit in the heavens; one of the celestial spheres.
n. - An interval of time in which a certain succession of events or phenomena is completed, and then returns again and again, uniformly and continually in the same order; a periodical space of time marked by the recurrence of something peculiar; as, the cycle of the seasons, or of the year.
n. - An age; a long period of time.
n. - An orderly list for a given time; a calendar.
n. - The circle of subjects connected with the exploits of the hero or heroes of some particular period which have served as a popular theme for poetry, as the legend of Arthur and the knights of the Round Table, and that of Charlemagne and his paladins.
n. - One entire round in a circle or a spire; as, a cycle or set of leaves.
n. - A bicycle or tricycle, or other light velocipede.
v. i. - To pass through a cycle of changes; to recur in cycles.
v. i. - To ride a bicycle, tricycle, or other form of cycle.
n. - A series of operations in which heat is imparted to (or taken away from) a working substance which by its expansion gives up a part of its internal energy in the form of mechanical work (or being compressed increases its internal energy) and is again brought back to its original state.
n. - A complete positive and negative wave of an alternating current; one period. The number of cycles (per second) is a measure of the frequency of an alternating current.