Source : Webster's Revised Unabridged Dictionary (1913)

Institutional \In`sti*tu"tion*al\, a.
   1. Pertaining to, or treating of, institutions; as,
      institutional legends.

            Institutional writers as Rousseau.    --J. S. Mill.

   2. Instituted by authority.

   3. Elementary; rudimental.

Source : WordNet®

institutional
     adj 1: relating to or constituting or involving an institution;
            "institutional policy"
     2: organized as or forming an institution; "institutional
        religion" [ant: {noninstitutional}]