noun ja·cobs·ite \ˈjākəbˌzīt sometimes -kəpˌsīt\

Definition of jacobsite



  1. :  a black magnetic isometric mineral MnFe2O4 consisting of an oxide of manganese and iron and constituting a member of the magnetite series

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.

Join MWU now and get access to America’s largest dictionary, with:

  • 300,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Origin and Etymology of jacobsite

French jakobsite, from Jakobsberg, Sweden, its locality + French -ite

Seen and Heard

What made you want to look up jacobsite? Please tell us where you read or heard it (including the quote, if possible).


capable of being understood in two ways

Get Word of the Day daily email!