Aspen

{ Asp″en (ăs″pĕn), Asp (ȧsp), } n. [AS. æsp, æps; akin to OHG. aspa, Icel. ösp, Dan. æsp, Sw. asp, D. esp, G. espe, äspe, aspe; cf. Lettish apsa, Lith. apuszis.] (Bot.) One of several species of poplar bearing this name, especially the Populus tremula, so called from the trembling of its leaves, which move with the slightest impulse of the air.