noun
plumb
pluhm
noun
1
A weight on a line used to check that something is perfectly vertical.
"The builder checked the wall with a plumb line."
adj
1
Exactly vertical.
"Make sure the fence post is plumb before you set the concrete."
adv
1
Exactly or completely.
"The arrow landed plumb in the centre of the target."
verb
1
To explore or think about something thoroughly, trying to fully understand it.
"The documentary plumbs the depths of his troubled childhood."
2
To connect something to a water supply and drainage system.
"They plumbed in a new washing machine."
How to Use Plumb
Learner’s notesIn plain EnglishExactly vertical, or to explore something deeply, or to connect to water pipes.
Common mistake
Don't confuse with "plum" the fruit — they sound alike but are unrelated.
Easily confused with
Common pairings
plumb line
plumb the depths
plumb in
Word Forms
more plumb comparative, plumbed past tense, plumbs plural, Plumbs plural, plumbs singular, most plumb superlative
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The builder checked the wall with a _____ line.
Etymology
From Old French, ultimately from Latin "plumbum" meaning lead — the metal traditionally used to weight the vertical measuring line.