'S' identifies a staff section in a battalion or brigade. Divisions, corps, major commands (MACOMs), and armies use 'G' identifiers, while joint commands use 'J'. The coding generally follows this convention:
- S(or G or J)-1: Personnel
- S-2: Intelligence
- S-3: Operations
- S-4: Logisitics
- S-5: Future Operations/Civil Affairs
- S-6: Communications
- S-8: Resource Management
Soldiers sometimes use the codes as slang to identify a job or task, such as calling the 18C the team S-4, as he's often responsible for keeping track of team equipment and supplies, as well as 'procurement'.