You say, "Since the word spiritual has as many definitions as there are people, it cannot be linked with experiences which can be empirically tested."
Spiritual is easy to define:
Spirituality has to do with the spirit, not as in ghosts, but as in the essence of being human — your soul or your inner life. Spirituality often has to do with religion, but it doesn't have to. ... Religions usually have defined beliefs, rituals, and guidelines; spirituality is more individual.
Empirical science is likewise easy to define--and ne'er the two shall meet.
As a philosophical dualist, that works especially well for me, as it keeps science and religion completely separate.
To me, your pained efforts to combine he empirical approaches of science with your evangelical atheism only work for you because you don't really understand science at all. I probably should let it pass, but the misuse of science is unacceptable.