Cousin John

• cuz john, cuzjohn, Cuz-John

From John (“outhouse; lavatory; chamber pot; toilet”). Possibly derived from a "euphemistic phrase of excuse" (e.g., "visiting my cousin John" or "going to cousin John's house"), similar to modern use of "powdering one's nose", but this is unattested.[1]

Cousin John (uncountable)

1. (US, slang, obsolete) A place or device for urination and defecation: an outhouse or chamber pot.
   • 1735, Richard Waldron, "A Freshman Guide", in 1953, William Bentinck-Smith, The Harvard Book, p. 162:

     20. No freshman shall mingo against the College wall or go into the fellows' cuzjohn.

   • 1741, "The Customs of Harvard College", in 1851, John Bartlett, A Collection of College Words and Customs, p. 319:

     18. No Freshman shall call or throw any thing across the College yard, nor go into the Fellow's Cuz-John.*

     *Abbreviated for Cousin John, i.e. a privy.

   • 2001, "Public Privies to Private Baths" in The Guide to United States Popular Culture, p. 645:

     American males often used British terms such as Cousin John or Jake to refer to a privy or a chamber pot.

• john (US); jakes (now chiefly Irish); see also Thesaurus:bathroom and Thesaurus:chamber pot