from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. manganese dioxide, occurring in hard tetragonal crystals

from the GNU version of the Collaborative International Dictionary of English

  • n. Manganese dioxide, occurring in tetragonal crystals nearly as hard as quartz.

from The Century Dictionary and Cyclopedia

  • n. Anhydrous manganese dioxid (MnO2), a mineral of a light steel-gray color and hardness nearly equal to that of quartz.


Ancient Greek to become grey. (Wiktionary)


Sorry, no example sentences found.


Log in or sign up to get involved in the conversation. It's quick and easy.