The tenable atmosphere ends at about 50 miles height, defined as the air being too thin to act on wings and control surfaces. Beyond that is space. Any ballistic trajectory, from a softball pitch to a cannon shot, to an ICBM flight is an orbital trajectory. Suborbital means that the orbit will not go all the way around the planet because it intersects the body of the planet so the flight will be a segment of a complete orbit. It's all orbital, and it is free ballistic flight in space, so it is orbital space flight and also the special case of suborbital flight.
The "thrust" [pardon the pun] was to try and get an idea of what cost would be associated with a space shot. If the cost was low enough, sub orbital, trans oceanic flight, could be accomplished in a very short time.
US to Sydney in 3 to 4 hrs?