Aromatherapy Glossary of Terms

Absolute A concentrated semi-solid aromatic material, usually obtained by alcohol extraction. More info
Antiseptic An agent that can inhibit the growth of disease-causing micro-organisms.
Antiviral An agent that opposes the action of viruses.
Aromatic A substance with a strong aroma or smell.
Attar Attars are essential oils that have been distilled using a unique process into a base of sandalwood oil. The sandalwood acts as a fixative and enhances the floral notes.
Bath Base In aromatherapy, a non-alcoholic agent that is used to distribute or dissolve essential oils evenly onto the surface of the bathwater. See also Dispersant.
Carrier Often a vegetable oil, but it can be a base cream, lotion, gel or shampoo etc which is used to dilute pure essential oils for application. More info
Chemotype Plants of the same genus which appear externally identical but have a variation in the chemical constituents, often due to climatic, altitude or soil conditions.
Chemovar This is an abreviation for 'chemotype variety' and is usually applied to the description of the plant, rather than the extracted oil.
Cold Pressed A natural physical process used to extract vegetable oils, and also essential oils from citrus fruits. Vegetable oils extracted in this way retain their essential fatty acid content since no heat or chemicals are used in the process. 
Compress A folded piece of material or lint applied hot or cold to the body. See How to use essential oils
Concrete A waxy semi-solid or solid material derived from plant material by a solvent.
Cultivar A variety of plant which has been developed as a result of cultivation, usually by means of hybridization.
Dispersant In aromatherapy; a non-alcoholic agent or surfactant that is used to distribute or dissolve essential oils evenly into the surface of water. See also Bath Base.
Essential oil The essence extracted from flowers, plants, herbs, leaves, fruits, woods and gums by steam distillation or other methods of extraction.
Fixed oil A vegetable oil, non-volatile. More info
Floral water See Hydrosol
Genus A category (in botany) ranking below a family and above a species which usually contains a group of species with similar characteristics.
Gum Any of various viscous substances exuded by plants and trees that dries on exposure to air  into water-soluble, non-crystalline, brittle solids.
Heartwood The central portion of a tree trunk.
Hydrolat See Hydrosol.
Hydrosol True hydrosols are produced by water or steam distillation of the flower or herb, and contain most of the hydrophilic (water soluble) molecules from the plant or flower material that did not distil into the essential oil. Also known as hydrolat, hydrolate, distillate water or floral water. More info
Infusion A remedy prepared by soaking plant material in vegetable oil or water. See also Phytol
Limbic system A group of brain structures that is responsible for our feelings, emotions, motivations and influences the endocrine and autonomic motor systems. It also plays an important part in learning and memory. This system includes the thalamus, hypothalamus, amygdala, and prefrontal cortex.
Lymphatic system Consists of lymph nodes linked by lymph vessels that carry the lymph fluid around the body. This system collects waste from the tissues, returning it to the blood after it has been purified.
Lymphatic drainage A specialised massage technique that encourages the flow of lymph fluid, thereby draining away pockets of water retention and toxins. See lymphatic system.
Maceration A remedy prepared by soaking plant material in vegetable oil or water. See also Phytol.
Naturopathy Naturopathic medicine is a field of healthcare which works with the body's own self-correcting mechanisms, or efforts to maintain homoeostasis.
Oleo resin A naturally occurring exudation from plants and trees that is a mixture of an oil and resin, such as the exudate from pine, frankincense and myrrh trees.
Olfaction The sense of smell.
Photo-toxicity Pigmentation or a sensitising reaction on the skin when exposed to ultra-violet light, due to a naturally occurring component in an essential oil i.e. - bergapten in Bergamot oil.
Phytol 1) A remedy prepared by soaking plant material in vegetable oil or water. See also Maceration. Not to be confused with:

2) A volatile oil produced by an advanced method of extraction (Phytonics process) utilising a solvent which boils at a temperature below freezing point and leaves no solvent residue. Technically known as a Cold Absolute.
Phytotherapy The treatment of disease by plants; herbal medicine
Psychoneuroimmunology (Psycho-neuro-immunology) This specialist field of research studies the relationship between the brain and immune system, and how they communicate with each other using various chemical messengers.
Rectification A process of re-distillation used with some essential oils to remove particular constituents.
Resin (natural) Any one of a class of yellowish brown solid, or semi-solid substances which are of vegetable origin exuded from plants and trees e.g; pine, frankincense and myrrh. They are soluble in ether, alcohol, and other solvents, but not in water.
Resinoid A material prepared from natural resinous matter such as gum resins.
Surfactant A surface-active agent that reduces the surface tension of two liquids. Used in aromatherapy, a surfactant acts as a dispersant between oil and water.
Synergy The effect of two or more agents working together to produce an effect that is greater than the sum of the parts.
Taxonomy The science or principles of classifying organisms (plants) in established categories according to similarities or evolutionary relationships.

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