The spirit has nothing to do with religion, invisible sky people or faith. I have a consciousness that other animals on this planet lack, that consciousness is my spirit. It is my essence, who I am beyond the physical manifestation of Steve, which is blood, muscle, and sadly, way too much fat. When I am dead I will no longer be Steve, just a lump of meat for microbes. My spirit is greater than my life force, consciousness is the key.
And language is flexible and constantly changing. Google it.