ultraviolet ray; invisible electromagnetic radiation with a wavelength shorter than that of visible light, used for sterilization and medical treatment but harmful to eyes in large amounts; also called [[紫外光|紫外光|zi3 wai4 guang1]]

infrared ray; invisible electromagnetic radiation with a wavelength longer than visible red light but shorter than microwaves, often used for medical treatment, communication, and detection

ultraviolet light; radiation beyond the violet end of the visible spectrum