Most people keep a can of WD-40 within arm’s reach and rarely think twice about it. It sits on garage shelves, under kitchen sinks, and in toolboxes—always ready to silence a squeak or loosen something stubborn. The blue-and-yellow can is so familiar that its label almost fades into the background. Yet despite how widely it’s used, the meaning behind the name WD-40 remains a mystery to many.
The question usually arises during a small, everyday battle. A rusted bolt refuses to turn. A garden hose nozzle won’t budge. You spray,
