chrismon

From Medieval Latin crismon (New Latin chrismus, chrismum, chrismos), of uncertain origin.[1] In the 18th century adopted in German as Chrismon or Chrismum, plural Chrismen.[2] English in the 19th century. The word was revived for a type of Christmas decoration in the mid 20th century, now with a popular etymology of its being a portmanteau of Christus + monogram.[3]

chrismon (plural chrismons or chrisma)

1. A Christogram.
   • 1869, Chambers's Journal‎, page 818:

     The sacred monogram or chrismon was extensively used by Constantine […] a crown of gold, enclosing the chrismon or mysterious monogram

2. (palaeography) A stylised siglum or character interpreted as an invocation of Christ in Merovingian and Carolingian documents.
   • 1970, Encyclopedia Britannica, volume 7, page 478:

     The document usually begins with a verbal invocation (such as In Dei nomine, amen) or a chrismon (often Christ's monogram formed from the letters XP)

3. A Christmas decoration with explicitly Christian religious symbolism.
   • 1964, The Lutheran Witness, volume 83, page 548:

     Chrismons were first made as tree decorations by members of the Lutheran Church of the Ascension, Daville, Va., in 1957.

In English scholarly usage, the meaning of chrismon (uncountable) is mostly limited to the Chi Rho monogram. In 18th-century German usage, by contrast, the term was expanded to include the derived cross-like sigla not only in Merovingian and Carolingian times but throughout the medieval period. English scholarly usage rarely adopts this extended usage specifically in the context of Merovingian and Carolingian paleography.

The modern term used in American Christianity is often capitalised, as Chrismon, and uses the plural Chrismons.