A device used for measuring current oil levels in engine based vehicles. The color of the oil found on your dip stick can give mechanicam insight as to the health of your vehicle. A dip stick can reveal when you are running low on oil, or when you have filled your engine with too much oil. It's usually a good idea to clean your dip stick with a clean rag before putting it back in the engine, as dirty oil can contain abrasive sediment, which can harm your engine's performance.