Absolute
Indicates a practice of using solvents or chemicals to extract essential oils from plants, where as authentic aromatherapy uses natural methods such as steam distillation, cold press or extraction by soaking plant petals in natural base oils like olive oil. Examples of absolute are: Jasmine, Rose, Vanilla.

Aromatherapy
The art and science of using essential oils for their therapeutic, emotional, physiological and aesthetic attributes and benefits.

Base notes
One- third of the scale method (top, middle, base) of identifying the evaporation and stability rate of essential oils. The fragrance from base ( ex: patchouli, myrrh) notes linger in the air the longest.

Botanical names
Usually a Latin nomenclature method to classify species of plants that share a similar structure, characteristic, origin, behavior and ancestry. More times than not the names will be used in italic.

Bulking
Is a cost reducing post distillation procedure of combining oil from one species with another, usually by vaporizing and then condensing the synthesized oils in a large vessel called a still.

Carrier oils
As the name implies, carrier oils assist in the delivery, transport and absorption rate of essential oils. They play a vital role in how fast or slow an essential oil will release its therapeutic volatile oils.

Cold pressed
We are familiar with manual or cold pressed extraction, which is probably the first process used to get oil from fruit rinds and flowers. In citrus the volatile oils are near the surface and tight squeezing is enough to capture the essential oil.

Diffuser
There are many different types of diffusers. In many ways an ancient incense burner uses the same process. Oils are placed inside a secure vessel, large or small, then fire is used to either heat water to produce steam aroma or the fire is placed directly below the chosen oil.

Effleurage
A steam distillation process that uses essential oils to saturate purified fat that  is placed on a glass surface. This is the original procedure for making pomades.

Essential oils
Essential oils are complex volatile oil essences that are extracted and released from plants, flowers, bark, citrus rinds and other natural plant sources and is the foundation of aromatherapy.

Extenders
A procedure that some distillers and manufacturers use to increase the volume of their essential oil supply. It is not uncommon for this type of method to adulterate authentic oils and make them less therapeutic, but it is becoming a moribund practice in the industry.

Extraction
Refers to the variety of methods (distillation, cold pressed, solvent, effleurage) used to release essential oil from plants.

Floral water
Another name for floral water is hydrosol. It refers to the aromatic water that remains after steam or cold press distillation of essential oils.

Infusion
Is the process of heating botanical material (herbs or petals) in water to release essential oils or adding essential oils to a base oil.

Photosensitivity
Some essential oils are sunlight sensitive and over exposure to the sun while wearing is not recommended and could in some cases cause an unhealthy reaction. Make it a habit to read the label precautions.

Perfume oil
For the purpose of aromatherapy perfume oil is all about proper blending of essential oils in base oils. Trying to keep all your ingredients natural and in the right ratios. Occasionally beeswax or alcohols are
used to adjust the thickness or liquidity.

Pure
Is typically used to mean no unnatural or synthetic chemical used in the making of essential oils, but in actual practice it is a very subjective term and does not have a “legal” definition in jurisprudence. Some labels indicating all natural or pure essential oil could in fact be adulterated oils.

Reconstituted
Here, knowing the source and using a gas chromatography (GC) makes all the difference. The technique of masking a authentic oil or seeking to restore a natural oil’s characteristics with a synthetic laboratory created oil. There are times when reconstituted may mean the blending of natural oils, but verified authentic and not reconstituted may be a safer and better oil.

Rectified
When neglected or careless steps are taken in the process of distilling that leaves unwanted botanical material inside an essential oil container it is called rectification. It does not mean that the oil is bad, only that visible particles are mixed in with the oil, but most aromatherapist will not accept rectified oil
from a distiller.

Synthetic fragrances
They are artificial complex compounds made in the laboratory, often promoted as authentic essential oils. They are substituted for natural oils as a way for manufactures to save money. Synthetic fragrances are used in candles, soaps and other products and should be avoided.

Synergy
In aromatherapy synergy blends are good. The positive therapeutic effects of one oil is enhanced by adding another beneficial oil, making the combined oil greater than either would be as a single oil applied separately.

Toxicity
This should be a mathematical certainty, but is not. The controversy surrounds which essential oil is used, what dosage, duration and what age is the user. There is no one standard, but toxicity refers to the over use of a particular oil to the degree that causes the negative effects to outweigh the positive therapeutic benefits.

Volatile
A complex aromatic compound that is influenced in some way by temperature, pressure and time. All these factors play a critical role in the behavior and characteristic of an essential oil.