The Collaborative International Dictionary of English v.0.48:

Meter \Me"ter\, Metre \Me"tre\, n. [OE. metre, F. m[`e]tre, L.
   metrum, fr. Gr. ?; akin to Skr. m[=a] to measure. See Mete
   to measure.]
   1. Rhythmical arrangement of syllables or words into verses,
      stanzas, strophes, etc.; poetical measure, depending on
      number, quantity, and accent of syllables; rhythm;
      measure; verse; also, any specific rhythmical
      arrangements; as, the Horatian meters; a dactylic meter.
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            The only strict antithesis to prose is meter.
                                                  --Wordsworth.
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   2. A poem. [Obs.] --Robynson (More's Utopia).
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   3. A measure of length, equal to 39.37 English inches, the
      standard of linear measure in the metric system of weights
      and measures. It was intended to be, and is very nearly,
      the ten millionth part of the distance from the equator to
      the north pole, as ascertained by actual measurement of an
      arc of a meridian. See Metric system, under Metric.
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   Common meter (Hymnol.), four iambic verses, or lines,
      making a stanza, the first and third having each four
      feet, and the second and fourth each three feet; --
      usually indicated by the initials C. M.

   Long meter (Hymnol.), iambic verses or lines of four feet
      each, four verses usually making a stanza; -- commonly
      indicated by the initials L. M.

   Short meter (Hymnol.), iambic verses or lines, the first,
      second, and fourth having each three feet, and the third
      four feet. The stanza usually consists of four lines, but
      is sometimes doubled. Short meter is indicated by the
      initials S. M.
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WordNet (r) 3.0 (2006):

common meter
    n 1: the usual (iambic) meter of a ballad [syn: common
         measure, common meter]