a small mass of lead or other heavy material, as that suspended by a line and used to measure the depth of water or to ascertain a vertical line.Compare plumb line.
adjective Also plum .
true according to a plumb line perpendicular.
Informal. downright or absolute.
adverb Also plum .
in a perpendicular or vertical direction.
exactly, precisely, or directly.
Informal. completely or absolutely: She was plumb mad. You're plumb right.
verb (used with object)
to test or adjust by a plumb line.
to make vertical.
Shipbuilding. horn (def. 32).
to sound with or as with a plumb line.
to measure (depth) by sounding.
to examine closely in order to discover or understand: to plumb someone's thoughts.
to seal with lead.
to weight with lead.
to provide (a house, building, apartment, etc.) with plumbing.
verb (used without object)
to work as a plumber.
Idioms for plumb
out of / off plumb, not corresponding to the perpendicular; out of true.
Origin of plumb
1250–1300; Middle English plumbe, probably <Anglo-French *plombe<Vulgar Latin *plumba, for Latin plumbum lead
SYNONYMS FOR plumb
2 vertical, straight, square.
SEE SYNONYMS FOR plumb ON THESAURUS.COM
OTHER WORDS FROM plumb
plumb·a·ble,adjectiveplumbless,adjectiveplumbness,nounre·plumb,verb (used with object)
penetrate, explore, unravel, fathom, delve, upright, straight, sheer, perpendicular, erect, sound, search, gauge, measure, straight up, up and down, get to the bottom of