Essential oil is a type of vegetable oil that has a thick liquid form when stored at room temperature. This oil has volatile properties and can provide a distinctive aroma. Essential oils are also known by several other names ranging from essential oils, volatile oils, and etheric oils.Essential oils can be used as a base for fragrances, perfume seeds, to medicinal oils. The compounds that make up essential oils are complex compounds, but generally there is one more powerful or dominant compound that dominates the aroma of the oil.