What is the term for an object that emits its own light?

The term for an object that emits its own light is "luminous." Luminous objects produce light as a result of a physical process, such as combustion or incandescence. For example, the sun, a light bulb, and fireflies are all luminous because they generate and emit light on their own.

In contrast, opaque objects do not allow light to pass through them, and thus they cannot emit light. Translucent objects allow some light to pass through but do not emit their own light; they can, however, scatter light that passes through them. Reflective objects can bounce back light that strikes them but do not generate light themselves. Understanding these distinctions highlights the unique property of luminous objects, which is their ability to create and emit light independently.