Or·gan·ic a.
 1. Biol. Of or pertaining to an organ or its functions, or to objects composed of organs; consisting of organs, or containing them; as, the organic structure of animals and plants; exhibiting characters peculiar to living organisms; as, organic bodies, organic life, organic remains.  Cf. Inorganic.
 2. Produced by the organs; as, organic pleasure. [R.]
 3. Instrumental; acting as instruments of nature or of art to a certain destined function or end. [R.]
    Those organic arts which enable men to discourse and write perspicuously.   --Milton.
 4. Forming a whole composed of organs. Hence: Of or pertaining to a system of organs; inherent in, or resulting from, a certain organization; as, an organic government; his love of truth was not inculcated, but organic.
 5. Chem. Of or pertaining to compounds which are derivatives of hydrocarbons; pertaining to, or denoting, any one of a large series of carbon-containing compounds which are related to the carbon compounds produced by biological processes (such as methane, oils, fats, sugars, alcohols, ethers, proteins, etc.) and include many substances of artificial production which may or may not occur in animals or plants; -- contrasted with inorganic.
 Note: Borderline cases exist which may be classified as either organic or inorganic, such as carbon terachloride (which may be viewed as a derivative of methane), but in general a compound must have a carbon with a hydrogen atom or another carbon atom attached to it to be viewed as truly organic, i.e. included in the subject matter of organic chemistry.
 Note: ☞ The principles of organic and inorganic chemistry are identical; but the enormous number and the completeness of related series of organic compounds, together with their remarkable facility of exchange and substitution, offer an illustration of chemical reaction and homology not to be paralleled in inorganic chemistry.
 Organic analysis Chem., the analysis of organic compounds, concerned chiefly with the determination of carbon as carbon dioxide, hydrogen as water, oxygen as the difference between the sum of the others and 100 per cent, and nitrogen as free nitrogen, ammonia, or nitric oxide; -- formerly called ultimate analysis, in distinction from proximate analysis.
 Organic chemistry. See under Chemistry.
 Organic compounds. Chem. Chemical substances which are organic5.  See Carbon compounds, under Carbon.
 Organic description of a curve Geom., the description of a curve on a plane by means of instruments. --Brande & C.
 Organic disease Med., a disease attended with morbid changes in the structure of the organs of the body or in the composition of its fluids; -- opposed to functional disease.
 Organic electricity. See under Electricity.
 Organic law or Organic laws, a law or system of laws, or declaration of principles fundamental to the existence and organization of a political or other association; a constitution.
 Organic stricture Med., a contraction of one of the natural passages of the body produced by structural changes in its walls, as distinguished from a spasmodic stricture, which is due to muscular contraction.
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 Chem·is·try n.
 1. That branch of science which treats of the composition of substances, and of the changes which they undergo in consequence of alterations in the constitution of the molecules, which depend upon variations of the number, kind, or mode of arrangement, of the constituent atoms. These atoms are not assumed to be indivisible, but merely the finest grade of subdivision hitherto attained. Chemistry deals with the changes in the composition and constitution of molecules. See Atom, Molecule.
 Note: ☞ Historically, chemistry is an outgrowth of alchemy (or alchemistry), with which it was anciently identified.
 2. An application of chemical theory and method to the consideration of some particular subject; as, the chemistry of iron; the chemistry of indigo.
 3. A treatise on chemistry.
 Note: ☞ This word and its derivatives were formerly written with y, and sometimes with i, instead of e, in the first syllable, chymistry, chymist, chymical, etc., or chimistry, chimist, chimical, etc.; and the pronunciation was conformed to the orthography.
 Inorganic chemistry, that which treats of inorganic or mineral substances.
 Organic chemistry, that which treats of the substances which form the structure of organized beings and their products, whether animal or vegetable; -- called also chemistry of the carbon compounds.  There is no fundamental difference between organic and inorganic chemistry.
 Physiological chemistry, the chemistry of the organs and tissues of the body, and of the various physiological processes incident to life.
 Practical chemistry, or Applied chemistry, that which treats of the modes of manufacturing the products of chemistry that are useful in the arts, of their applications to economical purposes, and of the conditions essential to their best use.
 Pure chemistry, the consideration of the facts and theories of chemistry in their purely scientific relations, without necessary reference to their practical applications or mere utility.
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 organic chemistry
      n : the chemistry of compounds containing carbon (originally
          defined as the chemistry of substances produced by living
          organisms but now extended to substances synthesized
          artificially)