Which word describes something that is bright or glowing?

The word "luminous" specifically denotes something that emits or reflects light, making it bright or glowing. This term is often used to describe objects like stars, the moon, or even certain materials that shine or radiate light in a significant way. It emphasizes the quality of brightness associated with light-producing or light-reflecting elements.

In contrast, the other words don’t convey the same bright or glowing quality. For instance, "opaque" refers to something that does not allow light to pass through, therefore lacking brightness. "Dull" describes a lack of brightness or vividness, indicating something that is not shiny or vibrant. Meanwhile, "subdued" relates to something that is softened or muted, suggesting a gentle or less intense quality rather than brightness. Understanding the specific meaning of "luminous" helps to distinguish it from these other terms, underlining its unique association with brightness and light.