A kneeler is a cushion (also called a hassock) or a piece of furniture used for resting in a kneeling position.
In many churches, pews are equipped with kneelers in front of the seating bench so members of the congregation can kneel on them instead of the floor. In a few other situations, such as confessionals and areas in front of an altar, kneelers for kneeling during prayer or sacraments may also be used. Traditionally, altar rails often have built-in knee cushions to facilitate reception of Holy Communion while kneeling.
A kneeler is also a part of the prie-dieu prayer desk.