n. One who presses down; an oppressor.n. Pl. depressores (dep-re-sō′ rēz). In anatomy, a muscle that depresses or draws down: as, the depressor anguli oris (the muscle which draws down the corner of the mouth).n. 3. In surgery, an instrument like a curved spatula used for reducing or pushing a protruding part into place.n. In electricity, a device, consisting of a generator or other source of electromotive force, placed in the return circuit of an electric system and having the function of keeping the potential in that circuit approximately the same as that of the ground.