n. A piece of lead or other metal attached to a line, used in sounding the depth of water, determining the vertical, etc.n. An instrument used by carpenters, masons, and others in adjusting erections to a vertical line; a plumb-rule.n. The pommel or knob on the hilt of a sword.n. A weight.n. A piece of lead formerly used by school-boys to rule paper for writing.To weight with plummets, or as with plummets.