Point of sale - Wikipedia
https://en.wikipedia.org/wiki/Point_of_sale
The point of sale (POS) or point of purchase (POP) is the time and place where a retail transaction is completed. At the point of sale, the merchant calculates the amount owed by the customer, indicates that amount, may prepare an invoice for the customer (which may be a cash register printout)...
Urban Dictionary: POS
https://www.urbandictionary.com/define.php?term=POS
pos. 1) Piece Of Shit 2) an abbreviation some companies use for Positively Outstanding Service. If you would clean that POS off the floor, that would really be a demonstration of POS.