Cartesius

Derived from Middle French Descartes, one of several surnames originating in the Reformation period denoting support for the compromise of religious charters for each municipality, indicating adherence to a Catholic or Protestant denomination. Compare also the surname of his mother Brochard and the Germanic variant Broschart, corresponding to pro- (“for, supporting, on behalf of”) +‎ charta (“charter”).

• (Classical Latin) IPA^(key): [karˈtɛ.si.ʊs]
• (modern Italianate Ecclesiastical) IPA^(key): [karˈt̪ɛː.s̬i.us]

Cartesius m sg (genitive Cartesiī or Cartesī); second declension

1. a surname famously held by:
   1. René Descartes (Latinized to Renātus Cartesius).

Second-declension noun, singular only.

¹Found in older Latin (until the Augustan Age).