cephalin /ˈsɛf.ə.lɪn/ noun1 •A phospholipid found particularly in the cells of nervous tissue; it is also the primary phospholipid in bacteria.In 1912 Howell reported the results of a study of the thromboplastic action of the tissues in which he showed that the active substance is a phosphatid having the general properties of cephalin. — 1916 formscephalins