Ornstein refers to a surname that can be associated with various individuals, including notable figures in academia, business, and the arts. One prominent example is Leonard Ornstein, a well-known physicist recognized for his contributions to the field of statistical mechanics and quantum theory. In addition to individuals, the term "Ornstein" may also relate to concepts in mathematics and statistics, such as the Ornstein-Uhlenbeck process, which is a stochastic process used to model systems that exhibit mean-reverting behavior. This process has applications in finance, physics, and other scientific disciplines.