Definition

Describing something that does not allow any light to pass through, meaning it is completely sealed against light.

Example

The lighttight box kept the contents safe from exposure to sunlight.

Conversation

I finally finished my new lamp design!

Oh nice! Is it lighttight like you wanted?

Yes, I made sure there are no gaps for light to escape.

That sounds perfect; I can’t wait to see it in action!

Synonyms & Antonyms

Root Explanation

Lighttight → This word is formed from "light" (from Old English *leoht*, meaning not heavy or bright) and "tight" (from Old English *tiht*, meaning firmly held or close). The word "lighttight" refers to something that is both bright and securely sealed against light.

Memory Tip

Think of something that is both 'bright' ('light') and 'firmly held' ('tight') — that's what lighttight means.

Visually Confused Words