Derivatives of glycerol in which one hydroxy group, commonly but not necessarily primary, is esterified with phosphoric acid and the other two are esterified with fatty acids.
See: fatty acids, lecithins, phosphoglycerides, phospholipids
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1357 (https://doi.org/10.1351/pac199567081307)
White Book, 2nd ed., p. 184 (https://www.qmul.ac.uk/bibliog/white.html)