Etymology From Middle English plumbe, plumme, from Old French *plombe, from Latin plumba, plural of plumbum.
1
A little mass of lead, or the like, attached to a line, and used by builders, etc., to indicate a vertical direction.
2
Nautical, Transport A weight on the end of a long line, used by sailors to determine the depth of water.
3
The perpendicular direction or position.
Customers turned away from rickety chairs, stands of drawers that refused to open, or had no handles, lop-sided wardrobes whose doors were out of plumb or whose mirrors were cracked.1950, Norman Lindsay, Dust or Polish?, Sydney: Angus and Robertson, page 61:
Etymology From Middle English plumbe, plumme, from Old French *plombe, from Latin plumba, plural of plumbum.
1
Truly vertical, as indicated by a plumb line.
2
Ball games, Cricket, Games, Hobbies, Lifestyle, Sports Describing an LBW where the batsman is hit on the pads directly in front of their wicket and should be given out.
Etymology From Middle English plumbe, plumme, from Old French *plombe, from Latin plumba, plural of plumbum.
1
In a vertical direction; perpendicularly.
Plumb down he drops.1667, John Milton, “(please specify the page number)”, in Paradise Lost. […], London: […] [Samuel Simmons], and are to be sold by Peter Parker […]; [a]nd by Robert Boulter […]; [a]nd Matthias Walker, […], →OCLC; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873, →OCLC:
Years ago the well plumb dried out, not a drop of water in there since.
1 more example
'Are you sure of that, M. Hardman?' 'I'm plumb certain.'.1934, Agatha Christie, chapter 9, in Murder on the Orient Express, London: HarperCollins, published 2017, page 143:
To determine the depth, generally of a liquid; to sound.
2
To attach to a water supply and drain.
The kitchen sink is now plumbed in / up.
3
Figuratively To think about or explore in depth, to get to the bottom of.
to plumb the depths of
Delving to the core of her heart, his blue-green eyes plumbed her psyche, stripping it of all defenses, all resolve.2011, Catherine Lanigan, The Texan:
1 more example
The pressure had been on City, on Guardiola, to deliver the trophy that Sheikh Mansour has craved since his takeover in 2008 but it was an occasion when the manager found a new way to lose, to plumb fresh depths of frustration.2021 May 29, David Hytner, “Chelsea win Champions League after Kai Havertz stuns Manchester City”, in The Guardian:
4
To use a plumb bob as a measuring or aligning tool.