# Jordan block

> English word · Noun

## Definitions
1. A Jordan block over a ring R (whose identities are the zero 0 and one 1) is a matrix composed of 0 elements everywhere except for the diagonal, which is filled with a fixed element λ ∈ R, and the superdiagonal, which is composed of ones.

## Etymology
Named after Camille Jordan.

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