n. [ F. plomb, L. plumbum lead, a leaden ball or bullet; cf. Gr. mo`lybos, mo`libos, mo`lybdos. Cf. Plummet, Plunge. ] A little mass or weight of lead, or the like, attached to a line, and used by builders, etc., to indicate a vertical direction; a plummet; a plumb bob. See Plumb line, below. [ 1913 Webster ]

Plumb bob. See Bob, 4. --
Plumb joint, in sheet-metal work, a lap joint, fastened by solder. --
Plumb level. See under Level. --
Plumb line. (a) The cord by which a plumb bob is suspended; a plummet. (b) A line directed to the center of gravity of the earth. --
Plumb rule, a narrow board with a plumb line, used by builders and carpenters. [ 1913 Webster ]

v. t. [ imp. & p. p. Plumbed p. pr. & vb. n. Plumbing ] 1. To adjust by a plumb line; to cause to be perpendicular; as, to plumb a building or a wall. [ 1913 Webster ]

2. To sound with a plumb or plummet, as the depth of water; hence, to examine by test; to ascertain the depth, quality, dimension, etc.; to sound; to fathom; to test. [ 1913 Webster ]

He did not attempt to plumb his intellect. Ld. Lytton. [ 1913 Webster ]

3. To seal with lead; as, to plumb a drainpipe. [ 1913 Webster ]

4. To supply, as a building, with a system of plumbing. [ 1913 Webster ]

adv. In a plumb direction; perpendicularly. “Plumb down he falls.” Milton. [ 1913 Webster ]

a. Perpendicular; vertical; conforming the direction of a line attached to a plumb; as, the wall is plumb. [ 1913 Webster ]

n. Leadwork [ R. ] [ 1913 Webster ]

n. [ L. plumbago leadwort, fr. plumbum lead; cf. F. plombagin. ] (Chem.) A crystalline substance said to be found in the root of a certain plant of the Leadwort (Plumbago) family. [ 1913 Webster ]

a. (Bot.) Pertaining to natural order (Plumbagineæ) of gamopetalous herbs, of which Plumbago is the type. The order includes also the marsh rosemary, the thrift, and a few other genera. [ 1913 Webster ]

a. Resembling plumbago; consisting of, or containing, plumbago; as, a plumbaginous slate. [ 1913 Webster ]

n. [ L., from plumbum lead. ] 1. (Min.) Same as Graphite. [ 1913 Webster ]

2. (Bot.) A genus of herbaceous plants with pretty salver-shaped corollas, usually blue or violet; leadwort. [ 1913 Webster ]

{ } a. [ L. plumbeus, from plumbum the metal lead. ] 1. Consisting of, or resembling, lead. J. Ellis. [ 1913 Webster ]

2. Dull; heavy; stupid. [ R. ] J. P. Smith. [ 1913 Webster ]