Enamel/ɪˈnæml/ Definition 1 of 4Pro Tip 1/2Biological Material Enamel refers to the protective outer layer of teeth in humans and many animals. Dentists often talk about preserving the enamel to prevent cavities. Pro Tip 2/2Irreplaceable Substance Tooth enamel doesn't grow back, so it's important to protect it from damage. Soda can erode your enamel if you drink too much.