Cabbage: While the origin of the nickname remains unclear, Prince Philip's pet name for his wife is "cabbage."
Gan-Gan: Kate Middleton revealed that Prince George calls his great-grandmother "Gan-Gan" in a documentary for the queen's 90th birthday. According to royal biographer Kitty Kelly, the term is used to describe great-grandmothers.
Tillabet: The queen actually referred to herself as "Tillabet" when she was a little girl, and once she got older, her friends and family began calling her "Lilibet."