A department is a part of a larger organization with a specific responsibility. For the division of organizations into departments, see departmentalization.

In particular:

• A government department in the United States and Switzerland corresponds to a ministry in other systems:
  • Department (US government)
  • Department (Swiss government)
• Department (subnational entity)
• Part of an institution such as a commercial company (see departmentalization) or a non-profit organization such as a university.
  • Academic department
• A department store is a retail store that includes many specialized departments such as clothing or household items.
• In the US military:
  • "Department" is a term used by the U.S. Army, mostly prior to World War I.
  • A naval Department is a section devoted to one of several major tasks.
• Part of a state or municipal government:
  • Fire department
  • Police department
• Département ("department") is the name given to an administrative district of France and several other French-speaking countries.