from Late Latin Langobardus, proper name of a Germanic people who conquered Italy 6c. and settled in the northern region that became known as Lombardy, from Proto-Germanic Langgobardoz, often said to mean literally "Long-beards," but perhaps rather from *lang- "tall, long" + 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.), from Old French Lombart "Lombard," also "money-changer; usurer; coward," from Italian Lombardo (from Medieval Latin Lombardus).
Lombards in Middle Ages were notable throughout Western Europe as bankers and money-lenders, also pawn-brokers; they established themselves in France from 13c., especially in Montpellier and Cahors, and London's Lombard Street (c.1200) originally was the site of the houses of Lombard bankers. French also gave the word in this sense to Middle Dutch and Low German. Lombardy poplar, originally from Italy but planted in North American colonies as an ornamental tree, is attested from 1766.