also (reflecting a variant pronunciation) Lumbard, late 15c., "native or inhabitant of Lombardy" in Italy, from Medieval Latin Lombardus (source also of Italian Lombardo), from Late Latin Langobardus, name of a Germanic people that originated in Scandinavia, migrated to the Elbe area 1c. C.E., then to Pannonia (5c.) and c. 568 under Albonius conquered northern Italy and founded a kingdom there.
The name is from Proto-Germanic *Langgobardoz, often said to mean literally "Long-beards" (see long (adj.) + beard (n.)), but according to OED the second element is perhaps rather from the proper name of the people (Latin Bardi). Their name in Old English was Langbeardas (plural), but also Heaðobeardan, from heaðo "war."
In Middle English the word meant "banker, money-changer, pawnbroker" (late 14c.), especially a Lombard or other Italian trading locally, before it was used in reference to the nationality. The name in Old French (Lombart, Lombert) also meant, in addition, "money-changer; usurer; coward." Lombards were noted throughout medieval Western Europe as bankers and money-lenders, also pawn-brokers. French also gave the word in this sense to Middle Dutch and Low German.
London's Lombard Street (c. 1200) originally was the site of the houses of Lombard (and other Italian) bankers, who dominated the London money-market into Elizabethan times. An old expression for "long odds, much against little" was Lombard Street to a China orange (1815, earlier to an egg-shell, 1763).