Please describe  what is oil and give me a list of it’s applications.

An oil is a chemical substance that is composed primarily of hydrocarbons and may be animal, vegetable or petrochemical in origin.
Oil is used in a wide range of applications and is essential to everyday human life. These are:
Cooking - edible vegetable and animal oils are used for various purposes in cooking and food preparation
Cosmetics - most facial cleansers, lotions and hair care products contain molecules that come from mineral and vegetable oils
Fuel - crude oil is refined and converted to diesel, gasoline or jet fuel to power cars, trucks and planes
Heating - petrochemical oil is used for heating
Painting - oil is used as a supporting medium for paints
Lubrication - oils are used in various engineering purposes as they do not easily adhere to other substance which makes them useful as lubricants
Religion - oil has been used throughout history as a religious medium. It is often considered a spiritually purifying agent and is used to anointing purposes
Health - oils holds lots of fats and medical properties, for example fish oil holds the omega-3 fatty acid which helps with inflammation and reduces fat in the bloodstream