Definitions

1. adjective

giving off or reflecting light; radiant

“The illuminous glow of the neon sign was visible from a block away.”

2. noun

something that gives off or reflects light

“The firefly’s body was an example of a natural, bioluminescent source of illuminous light.”

3. adjective

providing or promoting mental understanding or insight

“The professor’s illuminous explanation helped the students understand the complex concept.”