APA Dictionary of Psychology

a system for classifying odor qualities based on a scheme originally developed by Swedish botanist Carolus Linnaeus (1707–1778). According to this system, there are nine primary odor qualities: ethereal, aromatic, fragrant, ambrosiac, alliaceous, empyreumatic, hircine, foul, and nauseous. These qualities combine to produce the perceptions of smells. [Hendrik Zwaardemaker]