The Collaborative International Dictionary of English v.0.48:

Aconitic \Ac`o*nit"ic\, a.
   1. Of or pertaining to aconite.
      [1913 Webster]

   2. (Chem.) Pert. to or designating a crystalline tribasic
      acid, C6H6O6, obtained from aconite and other plants. It
      is a carboxyl derivative of itaconic acid. Both the
      natural forma from plants and the form prepared chemically
      have the trans-configuration. It is used in the
      manufacture of itaconic acid (propylene dicarboxylic
      acid). --MI11

   Syn: 1-propene-1,2,3-tricarboxylic acid, equisetic acid,
        citridic acid, achilleic acid [Webster 1913 Suppl. +PJC]