"Grout lines" refer to the lines or spaces between tiles or stones that are filled with a cement-like substance called grout.
Sentences with «grout lines»
Spray grout lines with 3 % hydrogen peroxide and allow to sit for about an hour. (wellnessmama.com)
And while many prefer white grout for a crisp modern look, I actually love seeing a narrow grout line in a soft gray or taupe. (theinspiredroom.net)
I also noticed the mortar man did messier grout lines on the right than he did on the left, so that has me all Bessied - out, too. (theletteredcottage.net)