Just checked & no mention of #QuarterDays, so time for a #nerdout
Back in the early 2000s I was proof-reading commercial leases: office space & small businesses including many fish & chip shops.
I had to make my own fun to maintain focus (fish & chip shop names aside). I soon learned that almost all these modern business leases stated that rent was to be paid quarterly - fair enough, I thought. But:
'on the standard Quarter Days'
FYI these are 25 March, 24 June, 29 September, 25 December.