noun
1.
a. : a Eurasian poplar ( Populus alba ) that is widely cultivated and naturalized in the United States and has whitish bark and leaves with a white-tomentose lower surface
b. : an aspen ( Populus tremuloides ) of the United States with small leaves and long petioles
2. : the wood of a tulip tree ( Liriodendron tulipifera )