Mortar used to fill gaps between tiles (5)
I believe the answer is:
grout
(Other definitions for grout that I've seen before include "Tile fixer" , "cement" , "Thin, fluid mortar" , "Mortar for tiling" , "plaster" .)
I believe the answer is:
grout
(Other definitions for grout that I've seen before include "Tile fixer" , "cement" , "Thin, fluid mortar" , "Mortar for tiling" , "plaster" .)