Do your children have nicknames you call them by? If so do the?

nicknames mean something or represent something? I have a daughter who is 12 and when she was little she loved the clock on the winnie the pooh movie that went "pooh-koo--- pooh-koo" so we started calling her pooh-koo. Then when her brother came along we just started calling him boo-boo ,cause it sounded cute with pooh-koo.I still call them these names , but try not to in public.