Bathwater is the water you fill a bathtub with for taking a bath. Before you climb in, you run the tap until the tub contains enough warm water to sit in comfortably. Once you've finished bathing, the bathwater gets drained away.

The word appears in the old saying “don't throw the baby out with the bathwater,” which means don't get rid of something valuable while you're trying to eliminate something bad. Imagine a parent so eager to empty a dirty tub that they accidentally toss out their baby along with the water! The phrase warns against making careless decisions when you're in a hurry to fix a problem. For instance, if your soccer team loses one game and immediately changes every single rule and strategy, you might be throwing out the good parts of your game plan along with whatever actually needs fixing. The saying reminds us to think carefully about what's worth keeping before making big changes.