There is a current trend attempting to differentiate 'ghost' from 'spirit'.
It seems to be at least partly based on the idea that 'ghost' has become a Hollywood term, and serious investigators should no longer use it. So, even the paranormal is not immune to the Orwellian newspeak of the politically correct brain-cell-sharing crowd.
To paraphrase Shakespeare: A corpse by any other name is just as dead.
Some are now using 'ghost' to refer to visible spectres, and 'spirit' for invisible ones. Well guess what? They're all invisible most of the time. Some are visible some of the time, and not necessarily to everyone at once. So if I see someone, and you don't, what term do we use? Ghirit? Spost? Oh, I really shouldn't give these people ideas.
Ghosts are dead people. Spirits are dead people. They are the same thing, and always have been. Stop arguing over semantics and concentrate on looking for proof that there are dead people among us. Changing the terminology does not constitute proof, it does not imply a 'better scientific approach', and it will not affect a sceptic's view of the paranormal. If you want to mess around with words and definitions, become a politician.
This kind of nonsense achieves nothing more than further division of paranormal groups into 'we're right, you're wrong' cliques. Sceptics love this, because if we don't agree amongst ourselves then they don't have to fight us all. A sceptic can pick on one clique and all the other cliques will side with him against the 'heretics in our midst'.
Paranormal investigation is already more subdivided than Christianity. We have no idea which clique is right, because nobody has absolute proof of an afterlife. It must be obvious that such proof is more likely to be found if paranormal groups work as a coherent team rather than competitive sects.
There are some methods of investigation I don't agree with, such as the use of infrared thermometers and motion sensors, and the reliance on overly sensitive EMF meters. I don't believe the orbs photographed by digital cameras are real. I will, however, look at evidence that could prove me wrong. So far I haven't seen any but I'll still look. I have, for example, recently changed my mind about the use of digital cameras (but not about orbs).
Stop playing with words. Concentrate on your work. That might get us somewhere.