port-o-john

From Port-a-John (“an American business”), from portable, -a-, & john (“a toilet; an outhouse”).

port-o-john (plural port-o-johns)

1. A portable toilet.
   • 2001, Joyce Carol Oates, Middle Age: A Romance, page 208:

     She tried not to notice the garage attendants observing her when she parked to use the phone booth, furtive as a woman slipping into a port-o-john under the scrutiny of male witnesses.

• See Thesaurus:toilet and Thesaurus:bathroom.