The sensation of perceiving light; brightness: a sudden light that made me blink. Physics Electromagnetic radiation that has a wavelength in the range from about 4,000 (violet) to about 7,700 (red) angstroms and may be perceived by the normal unaided human eye. Physics Electromagnetic radiation of any wavelength. A source of light, especially a lamp, a lantern, or an electric lighting fixture: Turn out the lights when you leave. The illumination derived from a source of light: by the light of the moon. The particular quantity or quality of such illumination: moved the lamp closer to get better light. The pathway or route of such illumination to a person: You're standing in his light. A mechanical device that uses illumination as a signal or warning, especially a beacon or traffic signal. Daylight. Dawn; daybreak. Something, such as a window, that admits illumination. Architecture One of two or more openings in a window divided by a mullion or mullions. A source of fire, such as a match or cigarette lighter. Spiritual awareness; illumination. Something that provides information or clarification: threw some light on the question. A state of awareness or understanding, especially as derived from a particular source: in the light of experience. Public attention; general knowledge: brought the scandal to light. A way of looking at or considering a matter; an aspect: saw the situation in a different light. Archaic Eyesight. One's individual opinions, choices, or standards: acted according to their own lights. A person who inspires or is adored by another: My daughter is the light of my life. A prominent or distinguished person; a luminary: one of the leading lights of the theater. An expression of the eyes: a strange light in her eyes. In Quaker doctrine, the guiding spirit or divine presence in each person. The representation of light in art.