phenol

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

• noun A caustic, poisonous, white crystalline compound, C₆H₆O, derived from benzene and used in resins, plastics, and pharmaceuticals and in dilute form as a disinfectant and antiseptic.
• noun Any of a class of aromatic organic compounds having at least one hydroxyl group attached directly to the benzene ring.

from The Century Dictionary.

• noun Phenyl alcohol, C₆H₅OH, more commonly called carbolic acid.
• noun The general name of a compound formed from benzene and its homologues by the substitution of hydroxyl for hydrogen in the benzene nucleus.

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

• noun (Chem.) A white or pinkish crystalline substance, C6H5OH, produced by the destructive distillation of many organic bodies, as wood, coal, etc., and obtained from the heavy oil from coal tar.
• noun Any one of the series of hydroxyl derivatives of which phenol proper is the type.
• noun (Chem.) pure crystallized phenol or carbolic acid.
• noun (Chem.) any one of a series of compounds which are at once derivatives of both phenol and some member of the fatty acid series; thus, salicylic acid is a phenol acid.
• noun (Chem.) any one of series of derivatives of phenol and carbinol which have the properties of both combined; thus, saligenin is a phenol alcohol.
• noun (Chem.) any one of a series of compounds having both phenol and aldehyde properties.
• noun See under Phthalein.

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

• noun organic chemistry, uncountable A caustic, poisonous, white crystalline compound, C6H5OH, derived from benzene and used in resins, plastics, and pharmaceuticals and in dilute form as a disinfectant and antiseptic; once called carbolic acid.
• noun organic chemistry, countable Any of a class of aromatic organic compounds having at least one hydroxyl group attached directly to the benzene ring.

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

• noun a toxic white soluble crystalline acidic derivative of benzene; used in manufacturing and as a disinfectant and antiseptic; poisonous if taken internally
• noun any of a class of weakly acidic organic compounds; molecule contains one or more hydroxyl groups