Source : Webster's Revised Unabridged Dictionary (1913)

Assessor \As*sess"or\, n. [L., one who sits beside, the
   assistant of a judge, fr. assid?re. See {Assession}. LL., one
   who arranges of determines the taxes, fr. assid?re. See
   {Assess}, v., and cf. {Cessor}.]
   1. One appointed or elected to assist a judge or magistrate
      with his special knowledge of the subject to be decided;
      as legal assessors, nautical assessors. --Mozley & W.

   2. One who sits by another, as next in dignity, or as an
      assistant and adviser; an associate in office.

            Whence to his Son, The assessor of his throne, he
            thus began.                           --Milton.

            With his ignorance, his inclinations, and his fancy,
            as his assessors in judgment.         --I. Taylor.

   3. One appointed to assess persons or property for the
      purpose of taxation. --Bouvier.

Source : WordNet®

assessor
     n : an official who evaluates property for the purpose of taxing
         it [syn: {tax assessor}]