What is the X in X-mas?
1610s, from Hanseatic League, medieval confederation of North German towns, from Medieval Latin Hanseaticus, from Middle Low German hanse "fellowship, merchants' guild," from Old High German hansa "military troop, band, company." Related to Gothic hansa "troop, company, multitude," Old English hos "attendants, retinue." Middle English borrowed hanse from Old French hanse and Medieval Latin hansa (both from Old High German) in sense of "a company of merchants" (late 12c.). Cf. hanshus "guild hall" (12c.).