A subclass of acidic glycosphingolipids. They contain one or more sialic acid (n-acetylneuraminic acid) residues. Using the Svennerholm system of abbrevations, gangliosides are designated G for ganglioside, plus subscript M, D, or T for mono-, di-, or trisialo, respectively, the subscript letter being followed by a subscript arabic numeral to indicated sequence of migration in thin-layer chromatograms. (From Oxford dictionary of biochemistry and molecular biology, 1997)