Rainproof means designed or treated to keep rain from getting through. A rainproof jacket sheds water so you stay dry underneath, even in a downpour. Rainproof boots protect your feet from puddles and wet grass. The word describes something that successfully blocks rain from soaking through.

People often confuse rainproof with waterproof, but there's a difference. Waterproof means completely impervious to water in any situation: you could submerge a waterproof watch underwater and it would be fine. Rainproof just means it handles rain well. A rainproof tent keeps you dry during a storm, but you wouldn't want to drop it in a lake.

Many rainproof items are treated with special coatings or made from tightly woven fabrics that cause water to bead up and roll off instead of soaking in. Think of how water beads on a freshly waxed car. Engineers and designers create rainproof gear by understanding how water behaves and building materials that make rain slide away harmlessly. When you're heading out on a rainy day, rainproof gear means the difference between arriving soggy and miserable or staying comfortable and dry.