Dictionary.com

1. the promised and expected deliverer of the Jewish people.
2. Jesus Christ, regarded by Christians as fulfilling this promise and expectation. John 4:25, 26.
3. (usually lowercase) any expected deliverer.
4. (usually lowercase) a zealous leader of some cause or project.
5. (italics) an oratorio (1742) by George Frideric Handel.

Etymonline.com

c. 1300, Messias, from Late Latin Messias, from Greek Messias, from Aramaic (Semitic) meshiha and Hebrew mashiah “the anointed” (of the Lord), from mashah “anoint.”

This is the word rendered in Septuagint as Greek Khristos (see Christ). In Old Testament prophetic writing, it was used of an expected deliverer of the Jewish nation. The modern English form represents an attempt to make the word look more Hebrew, and dates from the Geneva Bible (1560). Transferred sense of “an expected liberator or savior of a captive people” is attested from 1660s.

Discussion/Explanation

Messiah has counterparts, as can be seen above, in Late, Greek, Aramaic, and Hebrew. It is in the Septuagint – the Greek translation of the Old Testament (OT) – that we see the related term from which we get Christ.

Regardless of which translation used, it remains a term that marks the deliverer, the anointed one foretold to come and save His people. As Christians, we know the Messiah to be Jesus. We call Jesus the Christ or Jesus Christ as this designates the same thing, the same truth about Jesus. The works of the New Testament (NT) were written in Greek which is why we see the term “Christ” so often whereas the OT commonly used “Messiah” as it was written in Hebrew.