chrismon

Etymology
From (New Latin, , ), of  origin. In the 18th century adopted in German as or, plural. 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.

Noun

 * 1) A Christogram.
 * 2)  A stylised siglum or character interpreted as an invocation of Christ in Merovingian and Carolingian documents.
 * 3) A Christmas decoration with explicitly Christian religious symbolism.
 * 1) A Christmas decoration with explicitly Christian religious symbolism.
 * 1) A Christmas decoration with explicitly Christian religious symbolism.

Usage notes
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.