Musk, a substance with a strong, penetrating odor. It is obtained from a large abdominal gland of the male musk deer. Musk activates sperm cells during the mating season and its scent attracts females. Musk is an oily brownish liquid when fresh, a grainy powder when dried. Diluted with alcohol, it is used in perfumes to slow evaporation. The characteristic odor of musk is caused by a substance called muscone, or muskone, which can be synthetically produced. Other animals, such as the muskrat, and some plants yield musklike substances.