From Old English 'grūt' (coarse meal)—the building filler was named for its resemblance to grain porridge.
A thin mortar used to fill the gaps between tiles, stones, or bricks.
From Old English 'grūt' (coarse meal, groats), from Proto-Germanic *grūtą (coarse ground grain). Originally referred to the coarse sediment in brewing. The building sense developed because early grouts were made from coarse ground materials mixed