lavatory vs portapotty

lavatory

noun
  • A plumbing fixture for urination and defecation: a toilet. 

  • Handwashing as an act, particularly 

  • A laver: a washbasin. 

  • A room containing a toilet: a bathroom (US) or WC (UK). 

  • The ritual washing of hands after using the piscina to clean the communion vessels. 

  • A plumbing fixture used for washing: a sink. 

  • A piscina: the basin used for washing communion vessels. 

  • A lavabo: the basin used for washing one's hands before handling the Eucharist. 

  • The lavabo: the ritual washing of hands before handling the eucharist. 

  • A baptismal font: the basin used for baptism, used figuratively for the washing away of sins. 

  • A vessel or fixture for washing 

portapotty

noun
  • A portable restroom. 

How often have the words lavatory and portapotty occurred in a corpus of books? (source: Google Ngram Viewer )