The difficult adjective οσιος (hosios) means "sanctioned by the law of God or by nature" in the eloquent words of Liddell and Scott (A Greek-English Lexicon). God's divine nature can be clearly seen through what has been made (Romans 1:20), and is all about the harmonic oneness of all things (hence the many symmetries and preservations laws of physics: see Romans 8:28, John 17:21-23, Ephesians 4:3-6), which can be partaken in by men, who then thus become divine (2 Peter 1:4).

Language is ultimately a matter of common standards or rules: words are only words when they live in multiple heads at once. Feelings are private and thus lawless. Words are common and thus lawful. Our adjective οσιος (hosios), therefore, means lawful or: in harmonic agreement with the natural laws of God.

Since ultimately only the divinely-natured elements of creation (those are the ones that add up to a harmonic whole) are preserved, whereas everything dissonant must fall apart or is done away with, our word also reflects stability and perpetuity.

Our adjective οσιος (hosios) frequently translates the laden word חסיד (hasid), "holy one" (Acts 2:27, Psalm 16:10, 30:4, and so on), from the noun חסד (hesed), which is commonly translated with loving-kindness, but is essentially a legal term that reflects a kind of natural fidelity, but formalized in some binding contract. That makes our adjective not unlike δικαιος (dikaios), meaning right, righteous, just in a legal sense (from δικη, dike, justice or fairness).

Our word οσιος (hosios) differs from αγιος (agios), holy, in that the latter emphasizes separation, whereas the former emphasizes harmony. And it differs from ιερον (hieron), sacred, in that the latter describes things and our adjective people.

It's a mystery where our word comes from. It may share a root with εθος (ethos), custom, and hence with εθνος (ethnos), a defined social group, which comes from an ancient Proto-Indo-European reflexive personal pronoun that meant "ourselves" (and is thus not dissimilar to the term "we the people"). Our adjective is also strikingly similar to the correlative relative pronoun οσος (hosos), meaning how great, or how many. A very creative Greek poet might even have associated our word with the name Osiris.

Our adjective οσιος (hosios), lawful, is used 7 times, see full concordance, and from it derive: