And what does “Dad” mean?
According to the Webster’s Dictionary, it means “father”. Notice, it does not say “Father”. You really don’t see the difference between calling your dad “father” or calling some one else “Father So-and-so”? I taught for one year at a Catholic high school, and I left (wasn’t fired, they tried to sue me to force me to return) among other things because of the way everybody looked at me when I called the priest who came once a week “mister” and “sir”. They thought I was being purposedly rude.