1 Thessalonians 2:13....
“And we also thank God constantly for this, that when you received the word of God, which you heard from us, you accepted it not as the word of men but as what it really is, the word of God, which is at work in you believers.” (ESV)
This definitely identifies the “word” of God as something heard from the apostles, conveyed to them by their teacher, Jesus Christ. It wasn’t the “word of men” but the “word of God” much of which later became the scriptures that we read today.
But “the Word” (Logos) is also used as a title for the son of God which is confirmed in John 1:14-15...
“And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth. (John bore witness about him, and cried out, “This was he of whom I said, ‘He who comes after me ranks before me, because he was before me.’)” (ESV)
So we have two distinct meanings conveyed here....the written “word of God” conveyed in the scriptures....and the spoken word of God conveyed by his son. So the title means being a spokesman for God, which we can see by reading the words he spoke that were from his Father, not from himself.