Wavelength is a fundamental physical measurement defined as the spatial period of a wave—the distance over which the wave's shape repeats in a cycle. This property is crucial for describing various forms of energy transfer, including electromagnetic radiation, such as visible light, radio waves, and X-rays. It is often symbolized by the Greek letter lambda ($\lambda$) and is measured in units of length, commonly meters or their multiples. Wavelength is intrinsically linked to wave frequency; specifically, the product of wavelength and frequency determines the speed of the wave in a given medium. In the context of electromagnetic waves, the spectral distribution of energy across various wavelengths allows for the categorization of radiation types based on their measured scale.