What is incarnation?
1 In the beginning was the Word, and the Word was with God, and the Word was God. 2 He was in the beginning with God. 3 All things were made through him, and without him was not any thing made that was made. 4 In him was life, and the life was the light of men. 5 The light shines in the darkness, and the darkness has not overcome it.
14 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.
Incarnation is a word that means the union of the eternal Son of God with sinless human nature through the virgin birth. The deity of Christ and the humanity of Christ are two distinct natures that to do not mix to form a third sort of something rather they are two distinct natures forever united in the person of Jesus of Nazareth.
Per the Oxford Dictionary of the Christian church:
“The Christian doctrine of the Incarnation affirms that the eternal Son of God took flesh from His human mother and that the historical Christ is at once both fully God and fully man.”
The Word, God the Son, became flesh and dwelt among us. The incarnation is all about Immanuel! God with us. God the Son came to save His people from their sin (Matthew 1:21).
 Cross, F. L., & Livingstone, E. A. (Eds.). (2005). In The Oxford dictionary of the Christian Church (3rd ed. rev., p. 830). Oxford; New York: Oxford University Press.