1) Any platform on stage. For instance, the series of platforms for choral presentations are called choral risers, the rostrum on which a drumkit and drummer is positioned is the drum riser. 2) The vertical portion of a step which gives a set of treads its height. 3) A microphone which can be raised through a small trap in the stage floor to a convenient height for an actor. Usually positioned just upstage of the footlight position, centre stage.