The Collaborative International Dictionary of English v.0.48:

Divisional \Di*vi"sion*al\, a.
   That divides; pertaining to, making, or noting, a division;
   as, a divisional line; a divisional general; a divisional
   surgeon of police.
   [1913 Webster]

   Divisional planes (Geol.), planes of separation between
      rock masses. They include joints.
      [1913 Webster]