Analogy \A*nal"o*gy\, n.; pl. Analogies. [L. analogia, Gr. ?,
   fr. ?: cf. F. analogie. See Analogous.]
   1. A resemblance of relations; an agreement or likeness
      between things in some circumstances or effects, when the
      things are otherwise entirely different. Thus, learning
      enlightens the mind, because it is to the mind what light
      is to the eye, enabling it to discover things before
      hidden.
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   Note: Followed by between, to, or with; as, there is an
         analogy between these objects, or one thing has an
         analogy to or with another.
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   Note: Analogy is very commonly used to denote similarity or
         essential resemblance; but its specific meaning is a
         similarity of relations, and in this consists the
         difference between the argument from example and that
         from analogy. In the former, we argue from the mere
         similarity of two things; in the latter, from the
         similarity of their relations. --Karslake.
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   2. (Biol.) A relation or correspondence in function, between
      organs or parts which are decidedly different.
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   3. (Geom.) Proportion; equality of ratios.
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   4. (Gram.) Conformity of words to the genius, structure, or
      general rules of a language; similarity of origin,
      inflection, or principle of pronunciation, and the like,
      as opposed to anomaly. --Johnson.
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