Source : Webster's Revised Unabridged Dictionary (1913)

Senatorial \Sen`a*to"ri*al\, a. [F. s['e]natorial, or L.
   senatorius.]
   1. Of or pertaining to a senator, or a senate; becoming to a
      senator, or a senate; as, senatorial duties; senatorial
      dignity.

   2. Entitled to elect a senator, or by senators; as, the
      senatorial districts of a State. [U. S.]

Source : WordNet®

senatorial
     adj : of or relating to senators; "senatorial election"