- b : a certificate conferring military rank and authority; also : the rank and authority so conferred
- 2: an authorization or command to act in a prescribed manner or to perform prescribed acts : charge
- 3a : authority to act for, in behalf of, or in place of another
- b : a task or matter entrusted to one as an agent for another
- b : a government agency having administrative, legislative, or judicial powers
- c : a city council having legislative and executive functions
- 5: an act of committing something <commission of a crime>
- 6: a fee paid to an agent or employee for transacting a piece of business or performing a service; especially : a percentage of the money received from a total paid to the agent responsible for the business
- 7: an act of entrusting or giving authority
An officer is a member of an armed force or uniformed service who holds a position of authority. Commissioned officers derive authority directly from a sovereign power and, as such, hold a commission charging them with the duties and responsibilities of a specific office or position. Commissioned officers are typically the only persons, in a military environment, able to act as the commanding officer (according to the most technical definition of the word) of a military unit.
Non-commissioned officers (NCOs) in positions of authority can be said to have control or charge rather than command per se, although the use of the word "command" to describe any use of authority is widespread and often official.
Having officers is one requirement for combatant status under the laws of war, though these officers need not have obtained an official commission or warrant. In such case, those persons holding offices of responsibility within the organization are deemed to be the officers, and the presence of these officers connotes a level of organization sufficient to designate a group as being combatant.