Weeping willow and Willow tree

Weeping willow noun - Willow with long drooping branches and slender leaves native to China; widely cultivated as an ornamental.

Willow tree and weeping willow are semantically related. In some cases you can use "Willow tree" instead a noun phrase "Weeping willow".

Willow tree noun - Any of numerous deciduous trees and shrubs of the genus Salix.

Weeping willow and willow tree are semantically related. Sometimes you can replace phrase "Weeping willow" with "Willow tree", this phrases are similar.