It's a 4X in space.
There are Fleets and Flotillas (so those names are taken). Those are composed of Battle Groups (a unit containing 1 flagship, 1-2 battleships and 4-8 smaller ships like frigates and destroyers).
Now, Battle Group is quite a longish name... I would not mind something shorter and/or sounding better. Especially since those would be used a lot (and I'm not sure an abbreviation "GBs" or "B.G.s" would sound good and intuitive).
I was thinking of Squadrons, but those sound like "Fighter Squadron", definitely not like somethining containing battleships...
