Lambda (λ) is a symbol used to represent wavelength, which is the distance between consecutive peaks or troughs in a wave. Wavelength is a key characteristic of waves, including light, sound, and electromagnetic radiation. It is typically measured in meters, nanometers, or other units, depending on the type of wave being studied. In the context of light, shorter wavelengths correspond to higher frequencies and energy, while longer wavelengths correspond to lower frequencies and energy. For example, visible light ranges from about 400 nanometers (violet) to 700 nanometers (red). Understanding wavelength is essential in fields like physics, engineering, and communications.