Definition of adamantean in English:

adamantean

adjective

rare
  • Having the hardness or strength of adamant; = adamantine.

Origin

Late 17th century; earliest use found in John Milton (1608–1674), poet and polemicist. From classical Latin adamantēus of adamant (as typifying hardness; from adamant-, adamās + -eus: see -eous) + -an.

Pronunciation:

adamantean

/ˌadəmanˈtɪən/