Definition of Rhenan in US English:

Rhenan

adjective

Geology
rare
  • Of, relating to, or designating a stage of the Palaeozoic found in the Rhineland, later identified with the Lower Devonian or with the Siegenian and Emsian stages of this system.

Origin

Mid 19th century; earliest use found in Quarterly Journal of the Geological Society of London. From French rhénan, specifically use of rhénan Rhenish from classical Latin Rhēnānus of or originating from the Rhine from Rhēnus, the name of the River Rhine + -ānus.