Downtonian

noun2

1. •
   (slang) A fan of the television series Downton Abbey.

   • (As all Downtonians know, this, too, turns out to be felicitous when after much travail, cousin Matthew and Lady Mary happily wed at the beginning of season three.) — 2013
2. •
   A stage of strata at the base of the Devonian period.

   • The stage names of the Lower Devonian (Downtonian, Dittonian and Breconian) and of the Upper Devonian (Farlovian) are all derived from localities in Shropshire or Breconshire. — 2015