Cy'cle1, n.
(sī'kl), n. [Fr. cycle, L. Lat. cyclus, Gr. κύκλος, ring or circle.]
Sense 1. An imaginary circle or orbit in the heavens.
How gird the sphere With centric and eccentric scribbled o'er, Cycle and epicycle, orb in orb. Milton.
Sense 2. 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.
Wages, . . . bear a full proportion to the medium of provision during the last bad cycle of twenty years. Burke.
Sense 3. (Bot.) One entire round in a spire or circle; as, a cycle or set of leaves. Gray.
Calippic cycle;—so called from Calippus, who proposed it as an improvement on the Metonic cycle; a period of 76 years, or four Metonic cycles.—Cycle of eclipses, a period of about 6586 years, the time of revolution of the moon's node;—called Saros by the Chaldeans.—Cycle of indiction, a period of 15 years, employed in Roman and ecclesiastical chronology, not founded on any authorized period, but having reference to certain judicial acts which took place at stated epochs under the Greek emperors.—Cycle of the moon, or Metonic cycle, a period of 19 years, after the lapse of which the new and full moon return to the same day of the year;—so called from its inventor, Meton.—Cycle of the sun, or solar cycle, a period of 28 years, at the end of which time the days of the month return to the same days of the week. The dominical or Sunday letter is the same, and follows the same order; hence it is also called the cycle of the Sunday letter.