The most common use of the word floor in the Bible is in relation to the threshing floor. These floors near the town or village were a flat platform of stone or clay often in the open to insure the blowing wind for winnowing. Either walking animals or dragging sleds were used to separate the grain from the stock. Then it was winnowed by tossing it into the air.
Another use of the word is as the floor of a building. This is esp. seen in
International Standard Bible Encyclopedia (1915)