from The American Heritage® Dictionary of the English Language, 4th Edition
- prep. Law In the matter or case of; in regard to.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- prep. In the matter of; with regard to.
from The Century Dictionary and Cyclopedia
- In the matter of: used especially in legal phraseology.
Latin in rē : in, in + rē, ablative of rēs, thing, matter.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin, literally meaning "in the matter [of]" (Wiktionary)