An aromatic candle and diffuser
Credit: "Aromatic Candle" by Hugo.arg at the Samogitian language Wikipedia, licensed under CC BY-SA 3.0
This image is originally part of the article What is Aromatherapy? A Guide to a Holistic Practice
The most common method of application in aromatherapy is direct or indirect inhalation. A diffuser or other devices can be used for this.