From Wikipedia:
Obviously it took them a while for the term 'Starfleet' was settled on, but are there any satisfactory in-universe explanations for what the other names were? Divisions of Starfleet or the Federation maybe?
During production of early episodes of the original series, several details of the makeup of the Star Trek universe had yet to be worked out, including the operating authority for the USS Enterprise. The terms Star Service ("The Conscience of the King"), Spacefleet Command ("The Squire of Gothos"), United Earth Space Probe Agency ("Charlie X" and "Tomorrow Is Yesterday"), and Space Central ("Miri") were all used to refer to the Enterprise's operating authority, before the term "Starfleet" became widespread from the episode "Court Martial" onwards.
Obviously it took them a while for the term 'Starfleet' was settled on, but are there any satisfactory in-universe explanations for what the other names were? Divisions of Starfleet or the Federation maybe?