PLUMB, n. plum. L. plumbum, lead probably a clump or lump.
A mass of lead attached to a line, and used to ascertain a perpendicular position of buildings and the like. But the word as a noun is seldom used, except in composition. See Plumb-line.
PLUMB, a. Perpendicular, that is, standing according to a plumb-line. The post of the house or the wall is plumb. This is the common language of our mechanics.
PLUMB, adv. In a perpendicular direction in a line perpendicular to the plane of the horizon. The wall stands plumb.
Plumb down he falls.
1. Directly suddenly at once as a falling mass usually pronounced plump. He fell plumb into the water.
PLUMB, To adjust by a plumb-line to set in a perpendicular direction as, to plumb a building or a wall.
1. To sound with a plummet, as the depth of water. Little used.