An officer is a member of a group typically in the areas of the military, police, or some other form of authority. In a military service, an officer's typical role is to command and direct, maintain discipline and make plans and provisions for operation. Certain organizations have special criteria in order to achieve the status of officer.
In a military service, a commission is an order from the service's supreme authority, such as its commander-in-chief, authorizing an individual to legally hold a military rank, with all the privileges and responsibilities of said rank. A commission usually appoints an individual to hold an officer's rank.
In times of conflict, a temporary commission could appoint an officer to command rank to replace an incapacitated or killed commanding officer. Also, it is not uncommon to have commanding officers promote/demote their subordinates and thus grant/revoke their commissions.
- Main article: Ranks
With each species and organization came different rank structures among officers. Also, most officers had a specific role within an organization, such as science officer, tactical officer, security officer, etc.