This is an old old one. Back from when I lived in a small Texas town.
The old country doctor had just delivered a baby boy, the fifth of farmer Felix McAffee. He knew also it would be the fifth time he would not be paid for his services, because farmer McAffee never paid his bills.
Felix was beaming as always, happy to see a new hand on the family farm. “What do you think I should name the young tyke?” he asked the doctor. What’s popular name these days?
“How about RFD?” the doctor suggested.
“Oh, you must mean FDR, for Franklin Delano Roosevelt.”
“No, I mean RFD for Rural Free Delivery.”