Chief of Staff

American  

noun

1. the senior officer of the U.S. Army or Air Force, a member of the Joint Chiefs of Staff, responsible to the secretary of a service branch.

2. (lowercase) the senior or principal staff officer in a brigade or division or higher unit in the U.S. Army or Marine Corps, in a numbered unit in the U.S. Air Force, or in a unit in the U.S. Navy commanded by a rear admiral or one of higher rank.

3. (lowercase) the senior officer in command of a general staff, especially that of the military forces of a nation.

4. (lowercase) the head of any staff.

   the chief of staff for the First Lady.

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Chief of Staff British  

noun

1. the senior staff officer under the commander of a major military formation or organization

2. the senior officer of each service of the armed forces

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Etymology

Origin of Chief of Staff

First recorded in 1880–85

Example Sentences

Westminster had barely had time to digest the departure of the prime minister's chief of staff Morgan McSweeney, when we learnt that his Director of Communications Tim Allan was off as well.

From BBC

Within weeks of getting into office, he ditched his first chief of staff.

From The Wall Street Journal

Ruth Jones spoke after Sir Keir's closest aide Morgan McSweeney quit as his chief of staff on Sunday, saying he took "full responsibility" for advising him to appoint Peter Mandelson as US ambassador last year.

From BBC

In the process, he becomes the latest high-profile figure to leave Downing Street and the second in less than 24 hours after Morgan McSweeney resigned as Sir Keir's chief of staff.

From BBC

On Sunday, McSweeney resigned as Sir Keir's chief of staff over calls for someone to be held accountable for the decision to appoint Peter Mandelson as UK ambassador to the United States.

From BBC