The word "bed cushion" can be substituted with several synonyms, all referring to the same thing. A common synonym is "pillow," which is a cushion used to support the head while sleeping. "Headrest" is another term that can be used, which can be a cushion for the head or neck. "Bolster" is also a synonym, but it is a long narrow cushion that is used for the head, neck, or legs. "Mattress pad" is another term that can be used; it refers to the cushioning placed on top of a mattress for comfort. Finally, "cushion" itself can be a synonym, which refers to a soft object to sit or lay upon.