What is the meaning of the word "kathaub" (كَثَوْب) in the context of the removal of impurity, and does a drop of urine that has dried on a garment, with only its color remaining, become impure if it comes into contact with something pure and wet?

The aforementioned statement was mentioned by some Maliki jurists, and its meaning is that the drying of an impurity on something like a garment does not count as its removal. Rather, its ruling remains until it is removed by water. So, if an impurity dries on a garment or similar item and then comes into contact with something wet, it will contaminate it.