Any one of a group of organic compounds derived by replacing one or more of the hydrogen atoms in ammonia by organic groups. Primary amines have one hydrogen replaced, e.g. methylamine, CH₃NH₂. They contain the functional group –NH₂ (the amino group). Secondary amines have two hydrogens replaced, e.g. methylethylamine, CH₃(C₂H₅)NH. Tertiary amines have all three hydrogens replaced, e.g. trimethylamine. Amines are produced by the decomposition of organic matter.