The Collaborative International Dictionary of English v.0.48:

Tropical \Trop"ic*al\, a. [Cf. L. tropicus of turning, Gr. ?.
   See Tropic, n.]
   1. Of or pertaining to the tropics; characteristic of, or
      incident to, the tropics; being within the tropics; as,
      tropical climate; tropical latitudes; tropical heat;
      tropical diseases.
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   2. [From Trope.] Rhetorically changed from its exact
      original sense; being of the nature of a trope;
      figurative; metaphorical. --Jer. Taylor.
      [1913 Webster]

            The foundation of all parables is some analogy or
            similitude between the tropical or allusive part of
            the parable and the thing intended by it. --South.
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   Tropic month. See Lunar month, under Month.

   Tropic year, the solar year; the period occupied by the sun
      in passing from one tropic or one equinox to the same
      again, having a mean length of 365 days, 5 hours, 48
      minutes, 46.0 seconds, which is 20 minutes, 23.3 seconds
      shorter than the sidereal year, on account of the
      precession of the equinoxes.
      [1913 Webster]