grease
Grease is a solid or semisolid lubricant formed as a dispersion of thickening agents in a liquid lubricant. Grease generally consists of a soap emulsified with mineral or vegetable oil.
Application and importance of using grease
Grease is used to lubricate places where frequent lubrication with a liquid lubricant is not possible or cost-effective. For example, moving parts of a car's front end, greases, unlike oils, cannot perform the cooling and cleaning functions.
Engineering assessment and analysis
Lithium-based greases are the most commonly used; sodium and lithium-based greases have higher melting point (dropping point) than calcium-based greases but are not resistant to the action of water. Lithium-based grease has a dropping point at 190 to 220 °C (374 to 428 °F). However the maximum usable temperature for lithium-based grease is 120 °C. 
