Definition

A unit of measurement for the amount of light emitted by a source, or the open space within a tubular structure in biology.

Example

The lumen is used to measure the brightness of light bulbs.

Conversation

Did you know that a single light bulb can produce around 800 lumens?

Really? I had no idea it was that bright!

Yeah, it’s interesting how lumens measure brightness instead of watts.

That makes sense, I guess it’s all about the light output.

Synonyms & Antonyms

Root Explanation

Lumen → It originates from Latin 'lumen' (meaning light or illumination). The word 'lumen' directly refers to light or the quality of being illuminated.

Memory Tip

Think of the Latin word for light, 'lumen', to remember that it refers to illumination or brightness.

Visually Confused Words