There are several different types of lubrication used to reduce friction and wear between moving surfaces, each suited to specific applications. The main types include hydrodynamic lubrication, where a full fluid film separates surfaces; boundary lubrication, where a thin layer of lubricant prevents direct contact under high loads or slow speeds; and mixed lubrication, which is a combination of both. Additionally, elasto-hydrodynamic lubrication occurs in high-pressure, rolling contacts like gears and bearings, while solid lubrication involves materials like graphite or molybdenum disulfide used where liquids are ineffective. Choosing the right type ensures optimal performance, reduced wear, and extended equipment life.