mammy vs maw

mammy

noun
  • mamma; mother 

  • In the southern United States, a black nanny employed to look after white children; or in the antebellum South, a female slave who was close to the household and looked after the children. 

maw

noun
  • Mother. 

  • Any large, insatiable or perilous opening. 

  • Appetite; inclination. 

  • The mouth. 

  • A gull. 

  • The upper digestive tract (where food enters the body), especially the mouth and jaws of a fearsome and ravenous creature. 

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