Meaning

noun a graphic symbol consisting of 2 or more letters combined (usually your initials); printed on stationery or embroidered on clothing

originThe noun derives from the post-Classical Latin monogrammum, itself from the Byzantine Greek μονόγραμμον (monógrammon); compare the French and Middle French monogramme, as well as the Italian monogramma. The verb derives from the noun; compare the earlier adjective monogrammed and the slightly earlier noun monogramming.

Etymology from Wiktionary, CC BY-SA 3.0