Concept / expression : Galactic Stage
It is is used by scholars and sociologists to describe the community of spacefaring civilizations able to travel faster than light. The term is generally expressed like this: Civilization X has ascented onto the Galactic Stage.
The appearance of the civilization is noticed by other civilizations. Many scholars agree that this is the most significant event in the history of any civilization.
Civilizations come and go much like actors. Their appearance or debut is usually meek and barley noticed by the long established players and many disapear the same way, little noticed.
New civilizations that ascent to the Galactic stage are often suprised to find that seeingly endless space is divided into regions, areas and actually has declared borders and areas claimed by others.
The Terrans ascented with the help of the Sarans (it is not entirely unsual but relativley rare that a civilization gets external help to ascent and retains its independence from the helping civilization) and entered the Galactic stage with a bang that is a source of much discussion, malcontent and fear of others.
And also eliminated the Ferons shorty after.