What Does “Only Begotten” Mean in the Bible?
Only son. Jesus is the Only Begotten Son of God: the one and only Son of God by nature.
Today
In the Creed at Mass we say “the Only Begotten Son of God.”
Where it appears in the Bible
John 3:16; John 1:14
What the Bible says
John 3:16
For God so loved the world, as to give his only begotten Son; that whosoever believeth in him, may not perish, but may have life everlasting.
John 1:14
And the Word was made flesh, and dwelt among us, (and we saw his glory, the glory as it were of the only begotten of the Father,) full of grace and truth.
Douay-Rheims Bible (Challoner revision), public domain.
Source: Catechism 444