Prince William's special nickname for daughter Charlotte that only he uses

ok.co.uk:

Just like many families, the royal family also have affectionate nicknames for each other. Prince Philip was reportedly known around Buckingham Palace as PP and Prince Harry used to refer to the Duchess of Cambridge as ‘Cath’ instead of Kate, with many other names cropping up for Prince William, Princess Diana and even the Queen herself over the years.

Similarly, the Duke of Cambridge is said to have a sweet nickname for his six year old daughter Princess Charlotte, which is different from the one used by Kate.The sweet name was reportedly revealed in 2019, when Wills and Kate attended the Royal Chelsea Flower Show alongside their children, where Kate was judging some of the gardens prepared for the show.

Get exclusive celebrity stories and fabulous photoshoots straight to your inbox with OK!'s daily newsletter While the family were playing on the swings in the garden, William called out to Charlotte to ask her to give him a push, but instead of using her usual name, he called out for ‘Mignonette’.

In English, the French word Mignonette translates roughly as 'little sweet', with mignon meaning 'sweet' and 'ette' adding a cute element to it.