Eau de Cologne or simply cologne is a perfume originating from Cologne, Germany. Originally mixed by Johann Maria Farina in 1709, it has since come to be a generic term for scented formulations in typical concentration of 2–5% and also more depending upon its type of essential oils or a blend of extracts, alcohol, and water. In a base of dilute ethanol (70–90%), eau de cologne contains a mixture of citrus oils, including oils of lemon, orange, tangerine, clementine, bergamot, lime, grapefruit, blood orange, bitter orange, and neroli. It can also contain oils of lavender, rosemary, thyme, oregano, petitgrain, jasmine, olive, oleaster, and tobacco.

Perfume is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. Perfumes can be defined as substances that emit and diffuse a pleasant and fragrant odor. They consist of manmade mixtures of aromatic chemicals and essential oils. The 1939 Nobel Laureate for Chemistry, Leopold Ružička stated in 1945 that "right from the earliest days of scientific chemistry up to the present time, perfumes have substantially contributed to the development of organic chemistry as regards methods, systematic classification, and theory."