a type of tree that has long thin branches and grows near water, or the wood from this tree.——朗文当代大辞典

Any plant of the genus Salix, which consists of trees and shrubs of various sizes, widely distributed in temperate and cold regions, growing for the most part by the side of watercourses, characterized by very pliant branches and long narrow drooping leaves, and valued economically as furnishing osiers, a light smooth and soft wood, or a medicinal astringent bark, or grown ornamentally by the side of water.——牛津当代大辞典

The wood or osiers of any tree of this genus.——牛津当代大辞典  @en