Essential oil
A concentrated scented oil drawn from a plant, usually by steam distillation.
Also: otto, volatile oil
An essential oil holds the volatile, scented compounds of a plant. Most are made by distilling flowers, leaves, wood or peel with steam. It takes a very large weight of petals to give a small amount of oil, which is why rose oil, often called rose otto, is among the most costly. Lavender, ylang-ylang, neroli from orange blossom, and geranium are other flower oils. Essential oils are strong and are normally diluted before they touch skin.