An essential oil is a concentrated, hydrophobic liquid containing volatile aromatic compounds extracted from plants.
It may be produced by distillation, expression, or solvent extraction. Essential oils are used in perfumery, aromatherapy, cosmetics, incense, medicine, household cleaning products, and for flavoring food and drink.
They are valuable commodities in the fragrance and food industries.
Essential oil is also known as volatile oil and ethereal oil.
They are really the same term. There are less strong scents that are dissolved in water and not alcohol and have less of a scent. Perhaps that is what you wanted to compare.