What is the X in X-mas?
c.1400, "something used in tying or binding," from Middle French ligature (14c.), from Late Latin ligatura "a band," from Latin ligatus, past participle of ligare "to bind" (see ligament). In musical notation from 1590s; of letters joined in printing or writing from 1690s.
ligature lig·a·ture (lĭg'ə-chur', -chər)
The act of tying or binding.
A cord, wire, or bandage used for tying or binding.
A thread, wire, or cord used in surgery to close vessels or tie off ducts.