Master seaman (MS), or matelot-chef (matc) in French, is a non-commissioned member rank of the Canadian Navy, which is between leading seaman (LS) and petty officer 2nd class (PO2). Technically, the rank is actually an appointment, with appointees holding the rank of leading seaman. If demoted, a master seaman will become an able seaman or leading seaman depending on seniority However, the process to be appointed is very similar to that of a promotion, and holding the appointment of master seaman is a prerequisite to promotion to PO2.