Lombardy poplarPronunciation: /lɒmbədɪˈpɒplə/Definition of Lombardy poplar noun a black poplar of a variety which has a distinctive tall, slender columnar form. It arose as a mutation in Italy and is widely cultivated. Populus nigra variety italica, family Salicaceae Lombardy poplar in other Oxford dictionaries Definition of Lombardy poplar in the US English dictionary