graphite

n. form of carbon (used in pencil leads, as a lubricant, etc.), black lead

Graphite (named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): "to draw/write", for its use in pencils) is one of the allotropes of carbon. Unlike diamond, graphite is an electrical conductor, and can be used, for instance, in the electrodes of an arc lamp. Graphite holds the distinction of being the most stable form of solid carbon ever discovered. It may be considered the highest grade of coal, just above anthracite and alternatively called meta-anthracite, although it is not normally used as fuel because it is hard to ignite.
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Noun
1. used as a lubricant and as a moderator in nuclear reactors
(synonym) black lead, plumbago
(hypernym) carbon, C, atomic number 6
(hyponym) lead, pencil lead

n. (new spell.=Grafit) graphite, form of carbon, plumbago, carbon-based material used for many purposes

adj. graphite

n. graphite, blacklead, lubricant