1: A very large carriage, motorcar, or other 4 wheel vehicle, capable of carrying more than 8
people.
Derived from
hack --> carriage + Bus. Circa 1946, US.
2: The firing of a new writer.
Doroth Parker: "Go take the
hack bus but don't bus my papers."
3: A server hub for maliscious programming.
Walton wanted to show us his country estate, so we jumped in his
hack bus, but the
fool suffered from so much HUMAS that he couldn't remember exactly where his mansion was.