Aliphatic

Al`i*phat"ic, a. [Gr., , oil, fat.] (Org. Chem.)

Defn: Of, pertaining to, or derived from, fat; fatty; -- applied to compounds having an openc-hain structure. The aliphatic compounds thus include not only the fatty acids and other derivatives of the paraffin hydrocarbons, but also unsaturated compounds, as the ethylene and acetylene series.