ˌadəˈman.ˌtīn, -ēn, |adə|mant ə n adjective
Etymology: Middle English, from Latin adamantinus, from Greek adamantinos of steel, like a diamond, from adamant-, adamas steel, diamond
1. : made of or having the quality of adamant
these adamantine gates — John Milton
2. : rigidly firm : unyielding
3. : resembling the diamond in luster
4. : of or relating to the enamel of the teeth