Luminous

How to spell luminous

8 letters · 3 syllables

How to pronounce luminous

Say the part in capitals loudest.

What does luminous mean?

1. adjectiveGiving off or reflecting light, especially so as to glow in darkness.

Luminous in a sentence

• The diver wore a luminous watch that stayed visible deep underwater.

• The runners stuck luminous strips to their jackets for safety at night.

Where does luminous come from?

Language of origin: Latin

This word traces back to the Latin lumen, meaning 'light' or 'a source of light', and its derived adjective luminosus, which described something 'full of light' or 'shining'. English took it in through Old French lumineux during the fifteenth century, keeping the sense of brightness that radiates or glows. The same lumen root lights up a whole family of English words, including 'illuminate', 'luminary', and the scientific unit the 'lumen' still used to measure light output today. The spelling trap sits in the unstressed middle: the second vowel is a soft schwa, so writers can hesitate over 'luminous' versus an imagined 'luminus', but the -ous ending and the i of lumin keep it regular once you connect it to 'illuminate'.

How the word is built

• lumin- (from Latin lumen: light)
• -ous (adjective suffix: full of, having)