Definition of pennantite
: a mineral Mn9Al6Si5O20(OH)16 of the chlorite group consisting of basic silicate of manganese and aluminum isomorphous with thuringite
Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.
Start your free trial today and get unlimited access to America's largest dictionary, with:
- More than 250,000 words that aren't in our free dictionary
- Expanded definitions, etymologies, and usage notes
- Advanced search features
- Ad free!
Origin and Etymology of pennantite
Thomas Pennant †1798 Welsh naturalist + English -ite
Seen and Heard
What made you want to look up pennantite? Please tell us where you read or heard it (including the quote, if possible).