I googled 'permissum' and only got responses about taxes, or 'let', heh heh...
We had an interesting experience a few months ago. My wife had to go to Winnipeg for a business trip, and she stayed with relatives. We have a few lawyers, and a judge in the family, and the relatives had their old Latin books from grade school. They passed them on as gifts, and we all were in stitches from the written-in comments, and the doodling.