Definition of epistolarian in US English:

epistolarian

noun

literary
  • A writer of letters.

adjective

literary
  • That writes letters; devoted to letter-writing.

Origin

Early 19th century; earliest use found in Anna Porter (1780–1832), novelist. From classical Latin epistola epistle + -arian, after e.g. antiquarian, antiquarian.

Pronunciation

epistolarian

/ɪˌpɪstəˈlɛːrɪən/