Definition of Zöllner illusion in US English:

Zöllner illusion


  • An optical illusion in which long parallel lines appear to diverge or converge when crossed by rows of short oblique lines.

    • ‘The Poggendorff illusion was actually derived from another famous illusion - the Zöllner illusion.’
    • ‘It may be that the Zöllner illusion is caused by this impression of depth.’


Late 19th century: named after Johann K. F. Zöllner (1834–82), German physicist.


Zöllner illusion