2 definitions
for Plumb line
From The Collaborative International Dictionary of English v.0.48 :
Plumb \Plumb\ (pl[u^]m), 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]
From WordNet (r) 2.0 :
plumb line
n : a cord from which a metal weight is suspended pointing
directly to the earth's center of gravity; used to
determine the vertical from a given point [syn: perpendicular]
