The Collaborative International Dictionary of English v.0.48:

Compare \Com*pare"\, v. t. [imp. & p. p. Compared; p. pr. &
   vb. n. Comparing.] [L.comparare, fr. compar like or equal
   to another; com- + par equal: cf. F. comparer. See Pair,
   Peer an equal, and cf. Compeer.]
   1. To examine the character or qualities of, as of two or
      more persons or things, for the purpose of discovering
      their resemblances or differences; to bring into
      comparison; to regard with discriminating attention.
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            Compare dead happiness with living woe. --Shak.
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            The place he found beyond expression bright,
            Compared with aught on earth.         --Milton.
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            Compare our faces and be judge yourself. --Shak.
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            To compare great things with small.   --Milton.
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   2. To represent as similar, for the purpose of illustration;
      to liken.
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            Solon compared the people unto the sea, and orators
            and counselors to the winds; for that the sea would
            be calm and quiet if the winds did not trouble it.
                                                  --Bacon.
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   3. (Gram.) To inflect according to the degrees of comparison;
      to state positive, comparative, and superlative forms of;
      as, most adjectives of one syllable are compared by
      affixing "- er" and "-est" to the positive form; as,
      black, blacker, blackest; those of more than one syllable
      are usually compared by prefixing "more" and "most", or
      "less" and "least", to the positive; as, beautiful, more
      beautiful, most beautiful.

   Syn: To Compare, Compare with, Compare to.

   Usage: Things are compared with each other in order to learn
          their relative value or excellence. Thus we compare
          Cicero with Demosthenes, for the sake of deciding
          which was the greater orator. One thing is compared to
          another because of a real or fanciful likeness or
          similarity which exists between them. Thus it has been
          common to compare the eloquence of Demosthenes to a
          thunderbolt, on account of its force, and the
          eloquence of Cicero to a conflagration, on account of
          its splendor. Burke compares the parks of London to
          the lungs of the human body.
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WordNet (r) 3.0 (2006):

comparing
    n 1: the act of examining resemblances; "they made a comparison
         of noise levels"; "the fractions selected for comparison
         must require pupils to consider both numerator and
         denominator" [syn: comparison, comparing]