Definition
A 'hot-water bag' serves the same purpose as a hot-water bottle: a container filled with hot water to provide warmth. It's a simple tool for creating localized heat. It is designed to be held against the body for comfort or pain relief. Consider it a portable, reusable heat source. Often used for soothing aches, warming beds, or just providing a bit of coziness on a cold day. It's a low-tech solution with a big impact.