The term 'rate of speed' can be defined as the speed at which something moves or is done. It can be expressed in various ways, such as TEMPO (5 letters), CLIP (4 letters), PACE (4 letters), and GAIT (4 letters). TEMPO is the rate of speed of a piece of music, while CLIP is the rate of speed at which something moves or is done. PACE is the rate of speed at which someone walks or runs, and GAIT is the manner of walking or running.