Source : Webster's Revised Unabridged Dictionary (1913)

Cycle \Cy"cle\, n.
   (a) (Thermodynamics) 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.
   (b) (Elec.) 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.

Cycle \Cy"cle\ (s?"k'l), v. i. [imp. & p. p. {Cycled}. (-k'ld);
   p. pr. & vb. n. {Cycling} (-kl?ng).]
   1. To pass through a cycle of changes; to recur in cycles.
      --Tennyson. Darwin.

   2. To ride a bicycle, tricycle, or other form of cycle.

Cycle \Cy"cle\ (s?"k'l), n. [F. ycle, LL. cyclus, fr. Gr.
   ky`klos ring or circle, cycle; akin to Skr. cakra wheel,
   circle. See {Wheel}.]
   1. An imaginary circle or orbit in the heavens; one of the
      celestial spheres. --Milton.

   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.

   3. An age; a long period of time.

            Better fifty years of Europe than a cycle of Cathay.
                                                  --Tennyson.

   4. An orderly list for a given time; a calendar. [Obs.]

            We . . . present our gardeners with a complete cycle
            of what is requisite to be done throughout every
            month of the year.                    --Evelyn.

   5. 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.

   6. (Bot.) One entire round in a circle or a spire; as, a
      cycle or set of leaves. --Gray.

   7. A bicycle or tricycle, or other light velocipede.

   {Calippic cycle}, a period of 76 years, or four Metonic
      cycles; -- so called from Calippus, who proposed it as an
      improvement on the Metonic cycle.

   {Cycle of eclipses}, a period of about 6,586 days, the time
      of revolution of the moon's node; -- called {Saros} by the
      Chaldeans.

Source : WordNet®

cycle
     n 1: an interval during which a recurring sequence of events
          occurs; "the neverending cycle of the seasons" [syn: {rhythm},
           {round}]
     2: a series of poems or songs on the same theme; "schubert's
        song cycles"
     3: a periodically repeated sequence of events; "a cycle of
        reprisal and retaliation"
     4: the unit of frequency; one Hertz has a periodic interval of
        one second [syn: {Hertz}, {Hz}, {cycle per second}, {cycles/second},
         {cps}]
     5: a single complete execution of a periodically repeated
        phenomenon; "a year constitutes a cycle of the seasons"
        [syn: {oscillation}]
     6: a wheeled vehicle that has two wheels and is moved by foot
        pedals [syn: {bicycle}, {bike}, {wheel}]

cycle
     v 1: cause to go through a recurring sequence; "cycle thge
          laundry in this washing program"
     2: pass through a cycle; "This machine automatically cycles"
     3: ride a motorcycle [syn: {motorcycle}]
     4: ride a bicycle [syn: {bicycle}, {bike}, {pedal}, {wheel}]
     5: recur in repeating sequences

Source : Free On-Line Dictionary of Computing

cycle
     
         A basic unit of computation, one period of a computer
        {clock}.
     
        Each {instruction} takes a number of clock cycles.  Often the
        computer can access its memory once on every clock cycle, and
        so one speaks also of "memory cycles".
     
        Every {hacker} wants more cycles (noted hacker {Bill Gosper}
        describes himself as a "cycle junkie").  There are only so
        many cycles per second, and when you are sharing a computer
        the cycles get divided up among the users.  The more cycles
        the computer spends working on your program rather than
        someone else's, the faster your program will run.  That's why
        every hacker wants more cycles: so he can spend less time
        waiting for the computer to respond.
     
        The use of the term "cycle" for a computer clock period can
        probably be traced back to the rotation of a generator
        generating alternating current though computers generally use
        a clock signal which is more like a {square wave}.
        Interestingly, the earliest mechanical calculators,
        e.g. Babbage's {Difference Engine}, really did have parts
        which rotated in true cycles.
     
        [{Jargon File}]
     
        (1997-09-30)