lightbox

/L AY1 T B AA0 K S/
noun
  1. 1

    A box containing a source of light and a white, translucent cover, used to view photographic transparencies.

  2. 2

    A box containing fluorescent tubes or LED technology, used to treat people with seasonal affective disorder (SAD) and circadian rhythm disorders.

  3. 3

    A kind of pop-up that is overlaid across a web page while the rest of the content is dimmed.

  4. 4

    A backbox.

  5. 5

    A device used in phreaking that indicates when a telephone line is in use by means of a light.

Source: https://en.wiktionary.org/wiki/lightbox