Ultraviolet (UV) light is a type of electromagnetic radiation that comes from the sun and artificial sources like tanning beds. It has a wavelength shorter than visible light but longer than X-rays. UV light is divided into three categories: UVA, UVB, and UVC, each with different effects on living organisms. UV light plays a crucial role in the production of vitamin D in the skin, which is essential for bone health. However, excessive exposure can lead to harmful effects, such as skin damage and an increased risk of skin cancer. Protective measures, like using sunscreen, can help minimize these risks.