Musk is a class of aromatic substances commonly used as base notes in perfumery. They include glandular secretions from animals such as the musk deer, numerous plants emitting similar fragrances, and artificial substances with similar odors.Musk was a name originally given to a substance with a penetrating odor obtained from a gland of the male musk deer. The substance has been used as a popular perfume fixative since ancient times and is one of the most expensive animal products in the world. The name originates from the Late Greek μόσχος 'moskhos', from Persian 'mushk', from Sanskrit 'muska-s' "testicle", from Latin 'mus' "mouse" (so called, presumably, for resemblance; see muscle). The deer gland was thought to resemble a scrotum. Applied to various plants and animals of similar smell (e.g. musk-ox, 1744) and has come to encompass a wide variety of aromatic substances with similar odors, despite their often differing chemical structures.
Until the late 19th century, natural musk was used extensively in perfumery until economic and ethical motives led to the adoption of synthetic musk, which is now used almost exclusively. The organic compound primarily responsible for the characteristic odor of musk is muscone.
Modern use of natural musk pods occurs in traditional Chinese medicine.
The musk deer belongs to the family Moschidae and lives in Nepal, Tibet, India, Pakistan, China, Siberia and Mongolia. The musk pod is normally obtained by killing the male deer through traps laid in the wild. Upon drying, the reddish-brown paste inside the musk pod turns into a black granular material called "musk grain", which is then tinctured with alcohol. The aroma of the tincture gives a pleasant odor only after it is considerably . No other natural substance has such a complex aroma associated with so many contradictory descriptions; however, it is usually described abstractly as animalistic, earthy and woody or something akin to the odor of babies' skin.