Engine oil, or engine lubricant actually refer to well-developed lubricants, including oil, enhanced
with additive packages to produce suitable engine lubricants used for lubrication of various internal
combustion engines. The main function is to reduce wear on moving parts; it also cleans, inhibits corrosion,
improves sealing, and cools the engine by carrying heat away
from moving parts.
In engines, there are parts which move against each other, and the friction wastes otherwise useful power
by converting the kinetic energy to heat. It also wears away those parts, which could lead to lower efficiency
and degradation of the engine. To avoid this, engine oils are used.