The word child is used as a prophetic name of Jesus (Yeshua‘) in one passage in Isaiah. The promised Child shares several names with God. The same name is used of Jesus in the New Testament, but as a fairly generic title. It is the prophetic significance that makes it an important title for Jesus.
Child in Hebrew:
Strong’s Concordance number: 3206
Bible reference: Isa. 9:6
For to us a child is born,
to us a son is given,
and the government will be on his shoulders.
And he will be called
Wonderful Counselor, Mighty God,
Everlasting Father, Prince of Peace. (Isaiah 9:6 NIV)
The Greek Old Testament translates this word using paidion.
Child in Greek:
Strong’s Concordance number: 3813
Bible references: Matt. 1:20; 2:9-21; Luke 2:17, 34, 40
But when [Joseph] had considered this, behold, an angel of the Lord appeared to him in a dream, saying, “Joseph, son of David, do not be afraid to take Mary as your wife; for the Child who has been conceived in her is of the Holy Spirit. (Matthew 1:20)
The KJV translates the Greek word pais in Acts 4:27; 30 as “child.” The word “servant” is better in that context.