What is the X in X-mas?
fatty substance found in the yolks of eggs (among other places), 1861, from French lécithine (coined 1850 by N.T. Gobley), from Greek lekithos "egg yolk," + chemical suffix -ine (2). Greek lekithos is of unknown origin.
lecithin lec·i·thin (lěs'ə-thĭn)
Any of a group of phospholipids that on hydrolysis yield two fatty acid molecules and a molecule each of glycerophosphoric acid and choline. They are found in nervous tissue, especially myelin sheaths and egg yolk, and in the plasma membrane of plant and animal cells.
A fatty substance present in most plant and animal tissues that is an important structural part of cell membranes, particularly in nervous tissue. It consists of a mixture of diglycerides of fatty acids (especially linoleic, palmitic, stearic, and oleic acid) linked to a phosphoric acid ester. Lecithin is used commercially in foods, cosmetics, paints, and plastics for its ability to form emulsions.