# unknown quantity

> English word · Noun

## Definitions
1. A person or thing whose nature or value is a mystery.
2. Used other than figuratively or idiomatically: see unknown, quantity.

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