How to use nana in a sentence. As they were poor, owing to the amount of milk the children drank, this nurse was a prim Newfoundland dog, called Nana, who had belonged to no one in particular until the Darlings engaged her. Nana definition is - the mother of one's father or mother : grandmother — often used as a form of address. "Mark my words," he said, "it is some nonsense Nana has been putting into their heads; just the sort of idea a dog would have. Origin Mid 19th century child's pronunciation of nanny or gran.