# pinacoid

> English word · Noun

## Definitions
1. The face of a crystal parallel to two of the axes.

## Etymology
Ancient Greek πινάκιον (pinákion, “slab, tablet”) + -oid.

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