In a military organization, an assignment (or position) was a post of duty to which one was assigned. It was distinct from rank, which referred to a hierarchical level. For example, after gaining the rank of captain in the Imperial Navy, Thrawn was assigned as first officer aboard the Arquitens-class light cruiser Thunder Wasp. The term was also used for a particular mission or task that an individual, a group, or a ship, was given to do.