# perlite

> English word · Noun · frequency rank #74,390

## Definitions
1. An amorphous volcanic glass formed by the hydration of obsidian.
2. The lightweight insulating material and aggregate resulting from expanding perlite glass by heat.

## Etymology
From French perle (“pearl”) + -ite.

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