Source : Webster's Revised Unabridged Dictionary (1913)

Precedential \Prec`e*den"tial\, a.
   Of the nature of a precedent; having force as an example for
   imitation; as, precedential transactions.

         All their actions in that time are not precedential to
         warrant posterity.                       --Fuller.

Source : WordNet®

precedential
     adj : having precedence (especially because of longer service);
           "precedential treatment for senior members of the firm"