What does speed mean in this setting (launching things out of Earth Orbit)? Most of the time when I hear about something reaching some speed is space I think ab

What does speed mean in this setting (launching things out of Earth Orbit)? Most of the time when I hear about something reaching some speed is space I think about its speed relative to the launch site or the Earths surface. In orbit around the Sun Parkers speed is surely changing, relative to Earth, do to the different orbits. Does speed really have much meaning in this context?