# lightbox

> English word · Noun · frequency rank #80,620

## Definitions
1. A box containing a source of light and a white, translucent cover, used to view photographic transparencies.
2. A box containing fluorescent tubes or LED technology, used to treat people with seasonal affective disorder (SAD) and circadian rhythm disorders.
3. A kind of pop-up that is overlaid across a web page while the rest of the content is dimmed.
4. A backbox.
5. A device used in phreaking that indicates when a telephone line is in use by means of a light.

## Etymology
From light + box. In the Internet sense, originally the name of one specific technique.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/lightbox