dipalmitoylphosphatidylcholine /ˌdaɪˌpæl.mɪˌtoʊ.ɪlˌfɒs.fəˌtɪd.ɪlˈkoʊ.liːn/ noun1 •A major phospholipid in lung surfactant that reduces surface tension in the alveoli, helping keep the lungs open and preventing collapse during breathing. formsdipalmitoylphosphatidylcholines