cholinePronunciation: /ˈkəʊliːn, -lɪn/Definition of choline noun [mass noun] Biochemistry a strongly basic compound important in the synthesis and transport of lipids in the body. Chemical formula: HON(CH3)3CH2CH2OH Origin: mid 19th century: coined in German from Greek kholē 'bile'choline in other Oxford dictionaries Definition of choline in the US English dictionary