What is "christogram"

A Christogram ( Latin ) is a monogram or combination of letters that forms an abbreviation for the name of Jesus Christ, traditionally used as a Christian symbol. One of the oldest Christograms is the Chi-Rho. It consists of the superimposed Greek letters chi and rho , which are the first two letters of Greek " Christ". It was displayed on the labarum military standard used by Constantine I in AD 312. The IX monogram is a similar form, using the initials of the name "Jesus (the) Christ", as is the ΙΗ monogram , using the first two letters of the name "Jesus".

There were a considerable number of variants of "Christograms" or monograms of Christ in use during the medieval period, with the boundary between specific monograms and mere scribal abbreviations somewhat fluid. The name Iesus has the abbreviations IHS (also written JHS, IHC, or ΙΗΣ), the name Christus has XP (and inflectional variants such as XPO, XPS, XPI, XPO, XPM). In Eastern Christian tradition, the monogram ΙϹΧϹ (with titlo indicating scribal abbreviation) is used for in both Greek and Cyrillic tradition.

A Middle Latin term for abbreviations of the name of Christ is chrisimus. Similarly, Middle Latin crismon, chrismon refers to the Chi Rho monogram specifically.