A Christogram is a monogram or combination of letters that forms an abbreviation for the name of Jesus Christ, traditionally used as a Christian symbol. As in the case of Chrismon, the term Christogram comes from the Latin phrase "Christus Monogramma", meaning "monogram of Christ".
Different types of Christograms are associated with the various traditions of Christianity, e.g. the IHS monogram referring to the Holy Name of Jesus or ΙϹΧϹ referring to Christ.
Read more about Christogram: Eastern Christianity, Western Christianity