The terms fragrance oil and essential / aromatherapy oil are often used interchangeably, however, it is important to realise the differences between the two.
Although essential oils and fragrance oils can sometimes be used for the same purposes, they are chemically different and possess different properties.
This is a natural product extracted from plants. Essential oils contain aromatic / healing properties that are used in the practice of aromatherapy.
This is a synthetic, ie man made product. Fragrance oils do not possess the natural healing properties of essential oils and are essentially only a 'pleasant' aroma. These oils are therefore not effective therapeutically in the true sense of the word. Some fragrance oils contain a small percentage of essential oils, some do not.
Each product has a place of use and it is important therefore to establish what it is to be used for before deciding which to use.
Essential oils, as mentioned, contain specifice properties which aid in healing. Therefore, this is a specific reason to use them. They can also be used purely for fragance. However, as they are more expensive than fragrance oils, it would make sense to rather use the fragrance oils for this purpose. The fragrance oils are also availalbe in a wider variety of fragrances. Essential oils are volatile in nature, whereas the fragrance oils are not and therefore last longer.