Noun

Singular charcoal

Plural charcoals

charcoal (plural charcoals)

1. Impure carbon obtained by heating wood or other organic matter in the absence of oxygen.
2. A stick of black carbon material used for drawing.
   • 1879, Th Du Moncel, The Telephone, the Microphone and the Phonograph, page 166:

     He takes the prepared charcoal used by artists, brings it to a white heat, and suddenly plunges it in a bath of mercury, of which the globules instantly penetrate the pores of charcoal, and may be said to metallize it.

3. A drawing made with charcoal.
4. (color/colour) A very dark gray colour.

   charcoal colour:

Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood, sugar, bone char, or other substances in the absence of oxygen (see pyrolysis, char and biochar). The resulting soft, brittle, lightweight, black, porous material resembles coal and is 85% to 98% carbon with the remainder consisting of volatile chemicals and ash.

The first part of the word is of obscure origin, but the first use of the term "coal" in English was as a reference to charcoal. In this compound term, the prefix "chare-" meant "turn", with the literal meaning being "to turn to coal". The independent use of "char", meaning to scorch, to reduce to carbon, is comparatively recent and is assumed to be a back-formation from the earlier charcoal. It may be a use of the word charren or churn, meaning to turn; i.e. wood changed or turned to coal, or it may be from the French charbon. A person who manufactured charcoal was formerly known as a collier (also as a wood collier). The word "collier" was also used for those who mined or dealt in coal, and for the ships that transported it.

Charcoal, or biochar, is also an essential element in the composition of terra preta.