benzene

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A colorless, flammable, toxic, liquid aromatic hydrocarbon, C₆H₆, derived from petroleum and used in or to manufacture a wide variety of chemical products, including DDT, detergents, insecticides, and motor fuels.

from The Century Dictionary.

• noun A hydrocarbon (C₆H₆) formed whenever organic bodies are subjected to destructive distillation at a high temperature, and obtained commercially from coal-tar.
• noun Same as benzin or benzine.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) A volatile, very inflammable liquid, C6H6, contained in the naphtha produced by the destructive distillation of coal, from which it is separated by fractional distillation. The name is sometimes applied also to the impure commercial product or benzole, and also, but rarely, to a similar mixed product of petroleum.
• noun (Chem.) a closed chain or ring, consisting of six carbon atoms, each with one hydrogen atom attached, regarded as the type from which the aromatic compounds are derived. This ring formula is provisionally accepted as representing the probable constitution of the benzene molecule, C6H6, and as the type on which its derivatives are formed.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun organic chemistry An aromatic hydrocarbon of formula C6H6 whose structure consists of a ring of alternate single and double bonds.
• noun organic chemistry, in combination Sometimes used in place of the phenyl group

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a colorless liquid hydrocarbon; highly inflammable; carcinogenic; the simplest of the aromatic compounds