Chiefly British; graphite

ETYM Greek graphein to write: cf. French graphite. Related to Graphic.
Used as a lubricant and as a moderator in nuclear reactors; SYN. black lead, plumbago.
Blackish gray, laminar, crystalline form of carbon. It is used as a lubricant and as the active component of pencil lead.
The carbon atoms are strongly bonded together in sheets, but the bonds between the sheets are weak so that the sheets are free to slide over one another. Graphite has a very high melting point (3,500şC/6,332şF), and is a good conductor of heat and electricity. It absorbs neutrons and is therefore used to moderate the chain reaction in nuclear reactors.

ETYM Latin, from plumbum lead.
Any plumbaginaceous plant of the genus Plumbago.
Graphite; Botany, leadwort.
Alternate name for the mineral graphite.

A pencil of soft slate (or soapstone) used for writing on a slate. slate-pencil

1. A soft mass, especially of some loose, fibrous substance, used for various purposes.
2. A little mass, tuft, or bundle, as of hay.
3. (Archaic) A little mass of some soft or flexible material, such as hay, paper, or old rope yarn, used for retaining a charge of powder in a gun.