Where did the name “Jesus Christ” come from?
First of all, the name “Jesus” corresponds to the Greek “Iesous”, and the English spelling "Jesus" comes from the Latin equivalent “Iesus”. The Hebrew transliteration is “Yeshua” (ישוע) or in Aramaic “Yahushua”, which means God Saves.
In Greek, He is called “Iesous o Christós” (Χριστός), which translates to "Jesus the Anointed One". In Hebrew, it is “Yeshua the Messiah” (מָשִׁיחַ) or transliterated Mashiyach. The English translation evolved to “Jesus the Christ.”
Then the article “the” was eventually dropped. So in modern English, He is simply referred to as “Jesus Christ” and oftentimes just shortened to “Christ.”
Before He divested Himself of His divinity and was miraculously conceived and born as a mortal man, He was God Himself and was with God the Father. He represented God the Father as the Spokesman or the Word.
John 1:1 says:
“In the beginning was the Word, and the Word was with God, and the Word was God.”