Essential Oils Glossary for Beginners: A Complete Guide to Aromatherapy Terms

Welcome to the Essential Oils Glossary, your go-to resource for understanding aromatherapy terms, techniques, and product types. Whether you’re new to essential oils or looking to deepen your knowledge, this glossary helps you learn the language of aromatherapy so you can use your oils safely, confidently, and effectively.

A

Aromatherapy
The practice of using essential oils extracted from plants to promote physical, mental, or emotional well-being through inhalation, topical application, or diffusion.

Absolute
A concentrated aromatic oil extracted from delicate flowers (like jasmine or rose) using solvents instead of steam. Absolutes are used in perfumes and high-end aromatherapy.

Antibacterial
A term for essential oils like tea tree, lemon, or eucalyptus that naturally help inhibit the growth of bacteria.

Antifungal
Describes oils such as clove, tea tree, and lemongrass that help prevent or reduce fungal infections.

Antiviral
Oils such as eucalyptus, oregano, and ravintsara that support the immune system and help combat airborne viruses.

B

Base Note
The deepest, slowest-evaporating scent in a blend. Base note oils, like frankincense or cedarwood, create balance and longevity in diffuser blends or perfumes.

Blend
A mixture of two or more essential oils designed to achieve a specific purpose, such as relaxation, energy, or focus.

Botanical Name
The Latin name of a plant (for example, Lavandula angustifolia for lavender). Always look for this on your essential oil label to verify authenticity.

C

Carrier Oil
A neutral, plant-based oil used to dilute essential oils before topical use. Common carrier oils include jojoba, sweet almond, and fractionated coconut oil.

Cold Pressing
A mechanical method of extracting oils from citrus peels without heat. Used for oils like lemon, lime, and orange to preserve their natural fragrance.

Contraindication
A medical or physical condition that makes the use of certain essential oils unsafe, such as avoiding clary sage during early pregnancy.

D

Diffuser
A device that disperses essential oil molecules into the air for inhalation. Diffusers are available in several types, including ultrasonic, nebulizing, and heat-based.

Dilution
Mixing essential oils with a carrier oil to make them safe for skin contact. Standard dilution is 2% (about 12 drops per ounce of carrier oil).

Distillation
A method of extracting essential oils using steam or water vapor to separate aromatic compounds from plant material.

E

Essential Oil
A highly concentrated liquid containing volatile compounds from plants. Used for aromatherapy, cleaning, massage, and mood enhancement.

Energizing Oils
Oils like peppermint, lemon, and rosemary that boost alertness and increase focus.

Eucalyptus
A fresh, camphorous oil known for supporting respiratory health and helping relieve congestion.

F

Frankincense
An ancient resin-based essential oil known for promoting calm, improving skin tone, and enhancing meditation.

Fixative
A base oil or resin that helps slow the evaporation of top and middle notes in a blend, extending scent longevity.

Fractionated Coconut Oil
A liquid form of coconut oil that stays fluid at room temperature and makes an excellent carrier for essential oils.

G

GC/MS Testing
Gas Chromatography/Mass Spectrometry — a scientific test used to confirm the purity and composition of essential oils.

Grounding Oils
Oils such as vetiver, patchouli, and sandalwood that help create emotional stability and calm during stress.

H

Hydrosol
The aromatic water that remains after steam distillation. Hydrosols are gentle, making them perfect for facial sprays or linen mists.

Hot Oil
A term for oils that may cause a strong warming or burning sensation on the skin if not diluted properly (like cinnamon or oregano).

L

Lavender
A versatile oil used for relaxation, stress relief, sleep support, and minor skin irritation. It’s considered a must-have in every home.

Lemon
A citrus essential oil with strong cleansing and mood-boosting properties. Ideal for natural cleaning products and air freshening.

M

Middle Note
The “heart” of a blend that provides body and harmony. Middle notes like geranium and rosemary tie top and base notes together.

Massage Blend
A blend of carrier oil and essential oils formulated for therapeutic massage or relaxation.

N

Neat Application
Applying essential oils directly to the skin without dilution. This should only be done with extreme caution and for specific oils like lavender or tea tree.

Neroli
An essential oil distilled from orange blossoms. It’s used for stress relief, anxiety, and skincare due to its light floral scent.

O

Oxidation
The process by which essential oils deteriorate when exposed to air, heat, or light. Store oils in dark, airtight bottles to prevent spoilage.

P

Patch Test
A safety test done by applying a small amount of diluted oil to a patch of skin to check for irritation before full use.

Phototoxic
Describes citrus oils (like bergamot or lemon) that can increase skin sensitivity to sunlight, leading to burns or irritation.

R

Resin
A thick, aromatic substance extracted from tree sap, used in grounding oils like frankincense and myrrh.

Roller Bottle
A small bottle with a roll-on top, used for applying diluted oils conveniently to the skin.

S

Steam Distillation
The most common process for extracting essential oils, where steam releases volatile compounds from plant material.

Synergy Blend
A blend specifically crafted so the combined effect of the oils is greater than their individual benefits.

T

Tea Tree Oil
A potent antibacterial and antifungal oil often used for cleaning, skincare, and immune support.

Top Note
The first scent noticed in a blend, often light and refreshing. Examples include lemon, orange, and peppermint.

U

Ultrasonic Diffuser
A diffuser that uses water and ultrasonic vibrations to disperse essential oil mist throughout a room.

V

Viscosity
The thickness or flow rate of an oil. Thick oils like patchouli pour slowly, while thin oils like lemon pour easily.

Volatility
Refers to how quickly an oil evaporates. Top notes are highly volatile, while base notes evaporate slowly.

Y

Ylang Ylang
A floral essential oil known for its sweet aroma and relaxing, mood-lifting qualities. Often used in romance blends or perfumes.