Mike: In essence, it's called a snapper because when the payout on a $5 blackjack is made the dealer would lay a $5 chip down and "snap" the $2.50 onto the payout. I may have over-simplified the explanation but that's basically it. The previous gentleman's response to you was incomplete. He left out the part about the term "snapper" originating in the west and dating back decades. Atlantic City has only been around for a couple of years and therefore vintage gaming terminology hasn't caught on there yet.