mother ship

noun4

1. •
   A vessel, aircraft or spacecraft that serves or carries a smaller vessel or vessels that operate independently from it.
2. •
   The largest vessel in a fleet of spaceships, from which the fleet is commanded and smaller spacecraft can be launched.

   • One Tuesday evening early in October, 1960, he and his wife believed they say hovering near their home five or six flying saucers and their mother ship. — 1965
3. •
   The main source or supporter of something.
4. •
   The largest and most fearsome example of something.

   • SDCC is the mothership of all cons. It's enormous. It has the best stars. — 2015