Crowning is when the center face of a board is higher in the middle than both edges like an inverted “U”. Crowning is a often a response to excess moisture or dryness on one surface of the board or from sanding a cupped board smooth, which appears as a crowned board when the floor relaxes to its original position. Crowning is the opposite of cupping.
The downward formation of wood (floor) planking, caused when moisture is absorbed from above the wood (floor) planking.
When flooring boards appear to be thicker or curve up in the center of the face of each board. Usually caused by sanding when the wood is cupped.