What is "tropic month"

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.

2. [From Trope.] Rhetorically changed from its exact original sense; being of the nature of a trope; figurative; metaphorical.
   --Jer. Taylor.

   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.

   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, 2

3. 3 seconds shorter than the sidereal year, on account of the precession of the equinoxes.