A sine wave is a smooth, periodic oscillation that is a fundamental waveform in mathematics and physics. It is defined by the sine function, which describes how the wave varies over time or space. Sine waves are characterized by their amplitude, frequency, and phase, making them essential in various applications, including sound waves, light waves, and alternating current in electrical systems. Sine waves are often used to model simple harmonic motion, such as the movement of a pendulum or the vibrations of a guitar string. They are also crucial in signal processing and telecommunications, where they help in the analysis and transmission of signals. Understanding sine waves is vital for fields like engineering, music, and physics.