Example 1: A raincoat is waterproof because it keeps you dry during a rainstorm.
Example 2: Waterproof boots are great for puddles, so your feet do not get wet when you jump in them.
Example 3: A waterproof backpack can keep your books safe and dry from rain while you walk to school.
Fun Fact: Some people wear waterproof clothes when they go fishing, so they can stay dry and enjoy their time on the water!