# plumb line

> English word · Noun

## Definitions
1. A cord with a weight attached, used to produce a vertical line; a plummet.
2. Any vertical reference line.

## Etymology
From Middle English plumblyne, equivalent to plumb + line.

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