I started calling them nicknames online after participating in some school related email groups. Some of the parents in the group had had problems with school administrations spying on them online; that information was then used to undermine the parent's efforts to get school services. i have been lucky enough never to have had that kind of relationship with my kids' schools, but it's a habit I have kept.
They both have had various nicknames through the years. This pair of names is one we've all always been especially fond of because of how the girls got them. One of our family's favorite places to go is Sanibel Island. One fall our family went to the island with my mother-in-law as she recovered from surgery. We had a cottage on the beach and the kids were little enough that they lived to collect the shells.
One night we went out to eat. The restaurant had a musician. The girls were enchanted and sat perfectly attentive in their seats at out outdoor table. They had braids to tame their hair still wet from the beach. When they tipped the man to play some song for them he called them Patience and Prudence.
As he got ready to play their song, he told the story of the original Patience and Prudence and picked my elder timid and cautious daughter to be Prudence. He named my younger carefree and easy-going daughter Patience. Our family thought the names so accurate that they have just stuck. Even know, nearly a decade later, my girls will still answer to those names.