出典:Wiktionary
From Chrīstus + -o- + gramma. Nonce-usage in 19th-century German numismatics, used in parallel with German Christogramm for Latin monogramma Christi, from the later 20th century more frequently used in Latin-language literature on art history and epigraphy.
chrīstogramma n (genitive chrīstogrammatis); third declension