DEFINITION: Re-grouting is a process that involves removing the old and worn-out grout from between tiles or natural stone slabs, and replacing it with new grout. Grout is the material that is used to fill the spaces between tiles or stones to create a smooth, even surface. Over time, grout can become dirty, discolored, or cracked, which can detract from the appearance of the tiled or stoned surface. Re-grouting can help to restore the appearance of the surface and prevent further damage, such as water infiltration or shifting of the tiles.