# Poincaré disk

> English word · Noun

## Definitions
1. The hyperbolic plane, viewed as a disk so that Euclidean circles and lines Euclidean-perpendicular to the disk's surface are hyperbolic lines.

## Etymology
After Henri Poincaré.

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