Definition of floor
The phrase is English. How often you hear it will depend on the casino you are in. In French, it would probably be the tournament room manager. The phrase "call the floor" means "to call the casino or gaming room management". When playing poker indoors, we call the floor when we have a dispute. Generally, players can get along with each other. If not, the dealer will always be able to decide, but in really difficult situations, the floor will be called as the ultimate authority. The floor tries to be as fair and impartial as possible.
An example where you can call the flop
You are on the river and an opponent bets big. You're not sure whether to call the bet or fold. You think about it. Suddenly you make a move that might suggest you are folding your hand. Instantly your opponent calls your bluff. You let him know that you have not yet folded your hand and call the bet. Your opponent disagrees and assures you that your hand was folded. Sometimes it can be difficult to know who is right. In such a situation, the floor is called.