The Collaborative International Dictionary of English v.0.48:

pace \pace\ (p[=a]s), n. [OE. pas, F. pas, from L. passus a
   step, pace, orig., a stretching out of the feet in walking;
   cf. pandere, passum, to spread, stretch; perh. akin to E.
   patent. Cf. Pas, Pass.]
   1. A single movement from one foot to the other in walking; a
      step.
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   2. The length of a step in walking or marching, reckoned from
      the heel of one foot to the heel of the other; -- used as
      a unit in measuring distances; as, he advanced fifty
      paces. "The height of sixty pace ." --Chaucer.
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   Note: Ordinarily the pace is estimated at two and one half
         linear feet; but in measuring distances be stepping,
         the pace is extended to three feet (one yard) or to
         three and three tenths feet (one fifth of a rod). The
         regulation marching pace in the English and United
         States armies is thirty inches for quick time, and
         thirty-six inches for double time. The Roman pace
         (passus) was from the heel of one foot to the heel of
         the same foot when it next touched the ground, five
         Roman feet.
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   3. Manner of stepping or moving; gait; walk; as, the walk,
      trot, canter, gallop, and amble are paces of the horse; a
      swaggering pace; a quick pace. --Chaucer.
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            To-morrow, and to-morrow, and to-morrow,
            Creeps in this petty pace from day to day. --Shak.
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            In the military schools of riding a variety of paces
            are taught.                           --Walsh.
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   4. A slow gait; a footpace. [Obs.] --Chucer.
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   5. Specifically, a kind of fast amble; a rack.
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   6. Any single movement, step, or procedure. [R.]
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            The first pace necessary for his majesty to make is
            to fall into confidence with Spain.   --Sir W.
                                                  Temple.
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   7. (Arch.) A broad step or platform; any part of a floor
      slightly raised above the rest, as around an altar, or at
      the upper end of a hall.
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   8. (Weaving) A device in a loom, to maintain tension on the
      warp in pacing the web.
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   9. The rate of progress of any process or activity; as, the
      students ran at a rapid pace; the plants grew at a
      remarkable pace.
      [PJC]

   Geometrical pace, the space from heel to heel between the
      spot where one foot is set down and that where the same
      foot is again set down, loosely estimated at five feet, or
      by some at four feet and two fifths. See Roman pace in
      the Note under def. 2. [Obs.]

   To keep pace with or To hold pace with, to keep up with;
      to go as fast as. "In intellect and attainments he kept
      pace with his age." --Southey.

   To put (someone) through one's paces to cause (someone) to
      perform an act so as to demonstrate his/her skill or
      ability.
      [1913 Webster +PJC]