DEFINITION: Lippage refers to the unevenness or difference in height between adjacent tiles or stone slabs, where one edge is higher than the other. Lippage can occur when installing natural stone tiles or slabs that are not uniform in thickness or when the installation surface is not level. Lippage can not only be unsightly but can also create a trip hazard and affect the functionality of the surface. Grinding and honing techniques may be used to even out the surface of the stone tiles or slabs.