# invar

> English word · Noun

## Definitions
1. An alloy of iron containing 35.5% nickel, and having a very low coefficient of expansion.

## Etymology
Shortening of invariable.

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