lead
(so toxic that it's no longer used in pencils)

lead2   Pronunciation Key  (ld)
n.
  1. Symbol Pb A soft, malleable, ductile, bluish-white, dense metallic element, extracted chiefly from galena and used in containers and pipes for corrosives, solder and type metal, bullets, radiation shielding, paints, and antiknock compounds. Atomic number 82; atomic weight 207.2; melting point 327.5°C; boiling point 1,744°C; specific gravity 11.35; valence 2, 4. See table at element.
  2. A lead weight suspended by a line, used to make soundings.
  3. Bullets from or for firearms; shot: pumped the target full of lead.
  4.  
    1. Any of various, often graphitic compositions used as the writing substance in pencils.
    2. A thin stick of such material.

Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.


lead

\Lead\ (l[e^]d), n. [OE. led, leed, lead, AS. le['a]d; akin to D. lood, MHG. l[=o]t, G. loth plummet, sounding lead, small weight, Sw. & Dan. lod. [root]123] 1. (Chem.) One of the elements, a heavy, pliable, inelastic metal, having a bright, bluish color, but easily tarnished. It is both malleable and ductile, though with little tenacity, and is used for tubes, sheets, bullets, etc. Its specific gravity is 11.37. It is easily fusible, forms alloys with other metals, and is an ingredient of solder and type metal. Atomic weight, 206.4. Symbol Pb (L. Plumbum). It is chiefly obtained from the mineral galena, lead sulphide.

Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.


lead

\Lead\, v. t. [imp. & p. p. Leaded; p. pr. & vb. n. Leading.] 1. To cover, fill, or affect with lead; as, continuous firing leads the grooves of a rifle.

2. (Print.) To place leads between the lines of; as, to lead a page; leaded matter.
Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.


lead
Symbol: Pb
Atomic number: 82
Atomic weight: 207.19
Heavy dull grey ductile metallic element, belongs to group 14. Used in building construction, lead-place accumulators, bullets and shot, and is part of solder, pewter, bearing metals, type metals and fusible alloys.

Source: The Elements