The Master of Library and Information Science (MLIS) is the master's degree that is required for most professional librarian positions in the United States and Canada. The MLIS is a relatively recent degree; an older and still common degree designation for librarians to acquire is the Master of Library Science (MLS), or Master of Science in Library Science (MSLS) degree. In some universities, these degrees are denoted as MLISc or MLSc or MSLS, as in the case of M.S. for MSc.