The cannabis plant consists of a wide variety of chemicals and compounds. About 140 of these belong to a large class of aromatic organic hydrocarbons known as terpenes. Terpenes are a large class of molecules that are produced by many species of plants. They are the main ingredient in essential oils and are the fragrant compounds responsible for plants’ distinctive aromas. In other words, terpenes are what make cannabis smell like cannabis, pineapple and orange at the same time, or almost any other smell you can imagine.