Phenyl silicone fluid refers to a type of silicone-based fluid where some or all of the methyl groups in the silicone backbone are replaced with phenyl groups (C₆H₅-). This modification alters the properties of the fluid, typically increasing its thermal stability, resistance to oxidation, and compatibility with certain materials. Phenyl silicone fluids are commonly used in applications where these properties are advantageous, such as in high-temperature lubricants, mold release agents, and as components in cosmetics and personal care products.