Terpenes, or terps, are aroma compounds produced in the flower and leaves of the cannabis plant. They are responsible for the aroma characteristics of cannabis and are the primary elements of the essential oils in plants. Each strain of cannabis has a unique terpene profile, and different strains have distinctive aromas and flavors. Terpenes are produced in the trichomes, which are the mushroom-shaped, crystal-like resin glands that cover the flowers and leaves of the cannabis plant.

Terpenes are not unique to cannabis, and they make up the largest percentage of aromatic oils contained in most plants, foods, and herbs. They are naturally occurring chemical compounds found in plants and some animals. Terpenes are thought to protect plants from harsh weather and predators.

While nearly all plants contain terpenes, some of the more common sources people encounter them include cannabis, aromatic herbs like sage and thyme, and citrus fruits. There are about 400 known terpenes in cannabis, but experts have only linked a handful of them to specific effects. Terpenes play an important role in the aroma and flavor of a cannabis strain, and they potentially work in synergy with cannabinoids and other cannabis plant compounds to produce psychoactive effects.