Enamel is the hard white substance that forms the outer part of a tooth. (Collins Dictionary)
Enamel is a hard, shiny paint that is used especially for painting metal and wood. (Collins Dictionary)
Enamel is a substance like glass which can be heated and put onto metal, glass, or pottery in order to decorate or protect it. (Collins Dictionary)
An opaque or semi-transparent glossy substance that is a type of glass, applied by vitrification to metallic or other hard surfaces for ornament or as a protective coating. (Oxford Dictionaries)
A work of art executed in enamel. (Oxford Dictionaries)
The hard glossy substance that covers the crown of a tooth. (Oxford Dictionaries)
A paint that dries to give a smooth, hard coat. (Oxford Dictionaries)
Can Tooth Enamel Be Restored?
What is tooth enamel?