Holos - the holy. Sanctified and whole; the principle of wholeness, which is the principle of health; derivations include healthy, holy, holiday, Hail, German Heil, whole, holistic, holocaust, help and hell. Hell, coming from the Germanic word Hel, meant bright (Modern German Hell - bright), significant of a wholeness like the sun from which radiated light.
Wholeness is the central idea behind the Monad, most important to religious studies both modern and ancient. The oneness of the universe, the All-God, is the supreme principle of being whole, and therefore it is holy. This is how the term holiness came to be used to describe closeness with the divine. What was whole was also what was healthy; this is part of the process of self-realization, or the becoming whole of all the psyche's parts, in Jungian psychology. By the unification of the psyche, the individual achieves wholeness, and therefore a state of supreme health. The word "health" itself is a combination of the h-l root with -t, which literally means "the wholl-ed" or "the thing made whole".
Again, we see the usage of the materialistic -p sound in the word help; to help something means to aid it, usually in a material sense; saving something from (a worldly) danger for instance.
Holos is central to the Proto-Indo-European religion. As a process, it is individuation or the connection with the Monad or the All; as a state, it is supreme health and unity of all parts, an organic whole, functional and perfected. It is a return to the origin; proximity to the center of the universe.
There is a discrepancy whether the root was pronounced Holos or Solos; Latin mutation made Holos into Solos, and then into Solvos, and finally into Salvus, which means "health".
Therefore, respect the whole; principle of the Monad.