Hebrew and Greek definitions
The Hebrew for 'one' is 'Echad or Yachid'. 'Echad' means a 'united one' and
'Yachid' means an 'absolute, numerical one' and there are other forms of one in
the Hebrew but 'Echad' is used of God over and over. He is a united one.
Elohim is used for God the majority of times in the Old Testament and it is a
plural Hebrew word which means literally 3 or more. Used most of the time
with a singular pronoun when speaking of the one true God but it is used with a
plural pronoun at times too. Since the Bible is clear that there isn't but one true
God then wouldn't it be showing that this God is singular yet plural.
Adonay, ad-o-noy'; an emphatic form of 113 Adown, aw-done'; the Lord (used
as a proper name for God only):-(my) Lord.
Let's look at some ways that Adonay is used in the word.
"When the Greek word 'kai' which is 'and' in English connects two nouns of the same case, if the
article precedes the first noun and is not repeated before the second noun, the
latter always relates to the same person that is expressed or described by the
first noun i.e. it denotes a farther description of the first named person."
Check Titus 2:13 which says,
(Dana and Mantey, A Manual Grammer of the Greek New Testament, pg. 147)
"13 Looking for that blessed hope, and the glorious appearing of the great God and our Saviour Jesus Christ;"
Cross reference II Peter 1:1 quoting,
"1 Simon Peter, a servant and an apostle of Jesus Christ, to them that have obtained like precious faith with us through the righteousness of God and our Saviour Jesus Christ:"
Also check out Romans 9:5,
"5 Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen."
Tying this in with I Cor. 3:16,
"16 And without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the Spirit, seen of angels, preached unto the Gentiles, believed on in the world, received up into glory."