Myelin is defined as a fatty layer which coats some axons; an insulating material composed of fats and proteins. a fatty substance coating the axons of some neurons that facilitates the speed and accuracy of neuronal communication Moreover, Myelin is a lipid sheath that surrounds and insulates the axons of the central and peripheral nervous systems. It serves to increase the speed of nerve conduction; fatty sheath that wraps around neurons and enables them to transmit information more rapidly. Please see also Myelin sheath