Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubricants can be solids, solid/liquid dispersions, liquids, liquid-liquid dispersions or gases.
Fluid-lubricated systems are designed so that the applied load is partially or completely carried by hydrodynamic or hydrostatic pressure, which reduces solid body interactions. Adequate lubrication allows smooth, continuous operation of machine elements, reduces the rate of wear, and prevents excessive stresses or seizures at bearings.
When lubrication breaks down, components can rub destructively against each other, causing heat, local welding, destructive damage and failure. During oral processing (eating) of food products lubrication plays an important role, especially the role of saliva is important here.