Immanuel is a big word that means "God is with us". It is a special name given to a person named Jesus, who Christians believe is the Son of God. You know how sometimes you might feel scared or lonely, and you wish that someone was with you to help you feel better? Well, Christians believe that God sent Jesus to be with us and help us feel better. They believe that Jesus was born as a human on Earth, just like you and me, but he was also God at the same time. That's why he's called Immanuel - because it means that God is always with us, even when we can't see him.