Command is defined as?

Command is defined as the act of directing, ordering, or controlling by virtue of explicit statutory, regulatory, or delegated authority.

The Incident Commander works closely with Command Staff, such as the Public Information Officer, Safety Officer, and Liaison Officer, who support the command function at the Incident Command Post (ICP). As stated in FEMA official training material “the Incident Commander has overall authority and responsibility for conducting incident operations.”

Source: https://training.fema.gov/is/courseoverview.aspx?code=IS-100.c&lang=en