👉 A defined fluid, often referred to as a synthetic or engineered fluid, is a type of lubricant specifically formulated with precise chemical compositions and properties to meet particular industrial or mechanical requirements. Unlike conventional mineral oils, defined fluids are produced through controlled chemical processes and contain additives tailored for specific applications, such as high-temperature resistance, low friction, or enhanced durability. These fluids are commonly used in critical machinery and equipment where performance consistency, reliability, and longevity are paramount, making them indispensable in sectors like aerospace, automotive, and heavy manufacturing.