Source : Webster's Revised Unabridged Dictionary (1913)

Devotional \De*vo"tion*al\, a. [L. devotionalis.]
   Pertaining to, suited to, or used in, devotion; as, a
   devotional posture; devotional exercises; a devotional frame
   of mind.

Source : WordNet®

devotional
     adj : relating to worship; "a devotional exercise"