Definition of "sweetums"

‘I want more bacon.’ / ‘There’s more in the frying pan, sweetums,’ said Aunt Petunia, turning misty eyes on her massive son. ‘We must feed you up while we’ve got the chance … I don’t like the sound of that school food …’

1998 July 2, J. K. Rowling [pseudonym; Joanne Rowling], “The Worst Birthday”, in Harry Potter and the Chamber of Secrets (Harry Potter; 2), London: Bloomsbury Publishing