From Longman Dictionary of Contemporary Englishaspenas‧pen /ˈæspən/ noun [countable] HBPa type of tree from western North America with leaves that shake a lot in the wind
Examples from the Corpus
aspen• The maples and aspens along the roadsides were vibrant with color.• The forest had already been defoliated and the oaks and aspens were expending precious energy sending out a second flush of leaves.• Roads met at perfect right angles; the white farmhouses had groves of pale aspen surrounding them.• The young artist stayed at Jenks' ranch under the San Francisco Peaks for several weeks, painting the aspens.• Then there was a paleness of white trunks and bare delicate branches as they passed through aspens along a slope.Origin aspen (1300-1400) Old English æspe “aspen” 