Source : Webster's Revised Unabridged Dictionary (1913)

Kneeler \Kneel"er\, n.
   1. One who kneels or who worships by or while kneeling.
      --Tennyson.

   2. A cushion or stool to kneel on.

   3. (Eccl. Hist.) A name given to certain catechumens and
      penitents who were permitted to join only in parts of
      church worship.

Source : WordNet®

kneeler
     n 1: a person in a kneeling position
     2: a board (sometimes cushioned) for someone to kneel on