Lewis & Short

dissertĭo, ōnis, f. [2. dissero],

  1. I. destruction, abolition: cur exsecrabilis ista nobis solis velut dissertio juris humani est? Liv. 41, 24, 10 (dub., this not being the etym. sense of the word; al. dissaeptio, discerptio).
  2. II. The explanation, solution, Hier. in Matt. 13, 13.