The phrase already explains itself. It's the edge of the casino which is also the house to the players of the casino. Imagine having them the higher chance of winning over the gamblers on their casino. For example, Casino A has 1% more chance of winning over the player. It's the reason why players has the possibility of losing more in the long run, but it can be managed if you are good at it and if you are a experienced.
It's the advantage of the casino, it's hard to determine when will we be able to win against mmthe House but if we're lucky enough we will be able to win or choose games with lowerhoise Edge for a chance to win, many says we can't beat the house which is true but there were times that we might win when we're able to handle our game and stop when our stra2seems not working and only favors the house.