Is the word Cristo a Latin word?

There is no Latin Word cristo.

Latin does have the Word Christo, which is the dative and ablative form of "Christus" (a borrowing from the Greek Word "Χριστός" meaning "anointed") and means "to, for, by or with Christ/the anointed one".

There is also crista, which is the Word for "a crest" (e.g., a rooster's comb).