The Collaborative International Dictionary of English v.0.48:

Fraction \Frac"tion\, n. [F. fraction, L. fractio a breaking,
   fr. frangere, fractum, to break. See Break.]
   1. The act of breaking, or state of being broken, especially
      by violence. [Obs.]
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            Neither can the natural body of Christ be subject to
            any fraction or breaking up.          --Foxe.
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   2. A portion; a fragment.
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            Some niggard fractions of an hour.    --Tennyson.
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   3. (Arith. or Alg.) One or more aliquot parts of a unit or
      whole number; an expression for a definite portion of a
      unit or magnitude.
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   Common fraction, or Vulgar fraction, a fraction in which
      the number of equal parts into which the integer is
      supposed to be divided is indicated by figures or letters,
      called the denominator, written below a line, over which
      is the numerator, indicating the number of these parts
      included in the fraction; as 1/2, one half, 2/5, two
      fifths.

   Complex fraction, a fraction having a fraction or mixed
      number in the numerator or denominator, or in both.
      --Davies & Peck.

   Compound fraction, a fraction of a fraction; two or more
      fractions connected by of.

   Continued fraction, Decimal fraction, Partial fraction,
      etc. See under Continued, Decimal, Partial, etc.

   Improper fraction, a fraction in which the numerator is
      greater than the denominator.

   Proper fraction, a fraction in which the numerator is less
      than the denominator.
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The Collaborative International Dictionary of English v.0.48:

Complex \Com"plex\ (k[o^]m"pl[e^]ks), a. [L. complexus, p. p. of
   complecti to entwine around, comprise; com- + plectere to
   twist, akin to plicare to fold. See Plait, n.]
   1. Composed of two or more parts; composite; not simple; as,
      a complex being; a complex idea.
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            Ideas thus made up of several simple ones put
            together, I call complex; such as beauty, gratitude,
            a man, an army, the universe.         --Locke.
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   2. Involving many parts; complicated; intricate.
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            When the actual motions of the heavens are
            calculated in the best possible way, the process is
            difficult and complex.                --Whewell.
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   Complex fraction. See Fraction.

   Complex number (Math.), in the theory of numbers, an
      expression of the form a + b[root]-1, when a and b are
      ordinary integers.

   Syn: See Intricate.
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WordNet (r) 3.0 (2006):

complex fraction
    n 1: a fraction with fractions in the numerator or denominator
         [syn: complex fraction, compound fraction]