According to Strong's Concordance:

Christos : the Anointed One, Messiah, Christ Original Word : Χριστός, οῦ, ὁ Part of Speech : Noun, Masculine Transliteration : Christos Phonetic Spelling : (khris-tos') Definition : the Anointed One, Messiah, Christ Usage : Anointed One; the Messiah, the Christ.

And according to Wikipedia:

In Abrahamic religions, a messiah or messias (Hebrew: מָשִׁיחַ, romanized: māšīyaḥ; Greek: μεσσίας, messías; Arabic: مسيح, masîḥ; lit. 'the anointed one') is a saviour or liberator of a group of people. The concepts of mashiach, messianism, and of a Messianic Age originated in Judaism, and in the Hebrew Bible, in which a mashiach is a king or High Priest traditionally anointed with holy anointing oil.

The literal translation of the Hebrew word mashiach (המשיח, messiah), is 'anointed', which refers to a ritual of consecrating (dedicating for a special service) someone or something by putting holy oil upon it. It is used throughout the Hebrew Bible in reference to a wide variety of individuals and objects; for example, kings, priests and prophets, the altar in the Temple, vessels, unleavened bread, and even a non-Jewish king (Cyrus the Great).

Therefor to qualify as the Christ (Messiah), the person has to:

  • be a saviour or liberator of a group of people
  • a king
  • a high priest
  • a prophet
  • anointed with oil

Jesus meet all these requirements.

Requirement Scripture Reference
be a saviour or liberator of a group of people Let all the house of Israel therefore know for certain that God has made him both Lord and Christ, this Jesus whom you crucified. Acts 2:36 (ESV)
a king Nathanael answered him (Jesus), “Rabbi, you are the Son of God! You are the King of Israel! John 1:43
a high priest The LORD has sworn and will not change his mind, “You are a priest forever after the order of Melchizedek.” Psalm 110:4 (ESV); Hebrews 7:27-28
a prophet And you, child (Jesus), will be called the prophet of the Most High; for you will go before the Lord to prepare his ways, to give knowledge of salvation to his people in the forgiveness of their sins, because of the tender mercy of our God, whereby the sunrise shall visit us from on high to give light to those who sit in darkness and in the shadow of death, to guide our feet into the way of peace.” Luke 1:76-79 (ESV); Deuteronomy 18:15-19; Acts 3:22-26
anointed with oil As for the word that he sent to Israel, preaching good news of peace through Jesus Christ (he is Lord of all), you yourselves know what happened throughout all Judea, beginning from Galilee after the baptism that John proclaimed: how God anointed Jesus of Nazareth with the Holy Spirit and with power. Acts 10:36-38 (ESV)

According to John, one of the requirements for salvation is to confess Jesus is the Christ (1 John 2:22-23)