Lubrication
![Lubrication of the ship steam engine crankshaft. The two bottles of lubricant are attached to the piston and move while the engine is operating.](/Images/godic/202501/10/Steam_engine_lubrication5350.jpg")
Lubrication is the process or technique employed to reduce friction between, and wear of one or both, surfaces in proximity and moving relative to each other, by interposing a substance called a lubricant in between them. The lubricant can be a solid, (e.g. Molybdenum disulfide MoS2) a solid/liquid dispersion, a liquid such as oil or water, a liquid-liquid dispersion (a grease) or a gas.