A "half-wave" refers to a type of signal or wave that only includes one half of a complete cycle. In electrical engineering, this concept is often applied in half-wave rectifiers, which convert alternating current (AC) to direct current (DC) by allowing only one half of the AC waveform to pass through. This results in a pulsating DC output. In the context of physics, a half-wave can also describe the behavior of waves, such as sound or light, where only one peak or trough is present. This can be observed in various applications, including radio waves and acoustic waves, where understanding half-waves helps in analyzing wave patterns and their effects.