What is caulk?
Caulk definition - A waterproof filler and sealant that is used in building and repair to make joints watertight, common in bath tubs. The process of applying caulk is known as "caulking."
Ideal Home Garden Explains
Caulk is a common household tool that is used for many tasks around the house. It is used to seal gaps, fix tiles, cover holes, repair windows, and much more. Caulk is quick and simple, taking around a couple of hours to dry once applied. It can be used in every room in the house as an instant fix for a crack.