In plain words
The king God promised to send. “Christ” is the Greek word for the same thing.
The fuller definition
Hebrew for “anointed one.” The king God promised to send to his people. “Christ” is the Greek word for the same thing, so “Jesus Christ” means “Jesus, the Messiah.” Christians believe Jesus is that promised one.
Where it comes from
Isaiah 9:6–7; Mark 8:29
In The Bible: Its books, its translations, and how Lutherans read it.