(alk-en'il gli'sĕr-ō-fos-fō-lip'id), A phosphatidate in which at least one of the radicals attached to the glycerol is an alk-1-enyl rather than the usual acyl radical; that is, is derived from an aldehyde rather than an acid, hence the older trivial names phosphatidal and acetal phosphatid(at)e. Synonym(s): plasmenic acid