What Does the Incarnation Mean in Orthodox Christianity?

The Incarnation is the Christian confession that the eternal Son and Word of God truly became human in Jesus Christ without ceasing to be divine.

Why does this matter?

Orthodox Christianity teaches that Christ fully shares human nature and truly unites humanity with God.

Was Jesus partly God and partly human?

No. Orthodox teaching confesses Jesus Christ as fully divine and fully human, one Person in two natures.

See How Does the Orthodox Church Understand Salvation?