noun
dentin
DEN-tin/dˈɛntʌn/
Hard tissue beneath a tooth's enamel.
A broad layer of yellowish dentin lies between the enamel and the tooth's pulp.

Etymology
The Latin word for “tooth” combines with a substance-forming suffix to name a material of the tooth: specifically, the hard tissue beneath enamel and surrounding the pulp.
In context
the tooth under the white enamel is a hard tissue called dentin
More examples
- Exposed dentin can make a tooth sensitive to cold.
- The dentist removes decayed dentin before placing the filling.
- Enamel is harder than the dentin beneath it.
Forms
dentin
dentinal adjective — Relating to or consisting of dentin.
Similar words
- ivory
- Usually denotes dentin from animal tusks, especially as a material.