Mast is an administrative proceeding where a senior officer in the chain of command can impose non-judicial punishment (NJP) for disciplinary offenses that do not rise to the level of a courts-martial. It is also referred to as Captain's or Admiral's Mast depending upon the rank of the individual leading the proceeding.
Authority to impose non-judicial punishment is granted under Article 15 of the Uniform Code of Military Justice (UCMJ) and is used by all the services. The Marine Corps refers to the proceeding as "office hours" while the Army and Air Force refers to it as an "Article 15." The UCMJ is contained in Chapter 47 of Title 10 of the United States Federal Code (Federal Law).
Additionally, there are also instances where sailors can recognized by a commanding officer for outstanding performance at mast. Such a proceeding is called a "meritorious mast."