Bolsters are objects used to support or prop up something else. The term can be broken down into three crossword solutions: PROPS (5 letters), SHORESUP (8 letters), and BUTTRESSES (10 letters). PROPS are objects used to support something, such as a stage prop in a play. SHORESUP is an action that provides support, such as shoring up a wall with extra beams. BUTTRESSES are structures built to provide support, such as the BUTTRESSES of a cathedral. All three terms refer to different ways of providing support, which is the main purpose of bolsters.