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

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

• (chemistry) Of a class of organic compounds in which the carbon atoms are arranged in an open chain.