# Ebbinghaus illusion

> English word · Noun

## Definitions
1. An optical illusion whereby a disk appears smaller if surrounded by larger disks than if by smaller.

## Etymology
Named after its discoverer, the German psychologist Hermann Ebbinghaus (1850–1909).

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