Wordnet 3.0
NOUN (1)
1.
a mineral consisting of manganese dioxide;
an important source of manganese;
The Collaborative International Dictionary of English v.0.48:
Pyrolusite \Pyr`o*lu"site\, n. [Pyro- + Gr. ? to loose, or ? a
loosing.] (Min.)
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).
[1913 Webster]
WordNet (r) 3.0 (2006):
pyrolusite
n 1: a mineral consisting of manganese dioxide; an important
source of manganese