Any large group of volatile unsaturated hydrocarbons found in the essential oils of plants. There are over 800 variations, but the main ones used are: Myrcene (a musky herbal smell), a-Pinene (Pine scented), Caryophellene (Spicy scent), Limonene (very citrus), Humulene (Woody smell), and Linalool (Floral type scent).  Others used are Bisabolol, Geraniol, Eucalyptol, Terpineol, Ocimene, Valencene and Terpinolene.

All of which when combined with CBD, CBG, CBC, and other herbs have the ability to affect multiple targets within the body, improve absorption of the active ingredients, and have greater efficacy with their combination than without.