from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A soft, black to dark gray mineral, MnO2, the commonest and most important secondary ore of manganese.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A dark coloured mineral, consisting of manganese dioxide (MnO2), that is an important ore of manganese.
from the GNU version of the Collaborative International Dictionary of English
- n. Manganese dioxide, a mineral of an iron-black or dark steel-gray color and metallic luster, usually soft. Pyrolusite parts with its oxygen at a red heat, and is extensively used in discharging the brown and green tints of glass (whence its name).
from The Century Dictionary and Cyclopedia
- n. Native manganese dioxid (MnO2), a common ore of manganese, occurring crystallized and massive, of a gray-color and metallic luster.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a mineral consisting of manganese dioxide; an important source of manganese
German Pyrolusit : Greek puro-, pyro- + Greek lousis, a washing (from louein, to wash; see leu(ə)- in Indo-European roots).(American Heritage® Dictionary of the English Language, Fourth Edition)