Willow bell is a term commonly used to describe the small, intricately-shaped flowers of the willow tree. These delicate blooms produce an unmistakable sound as the breeze sweeps through the branches, making them a favorite of naturalists and poets alike. Synonyms for the term include "catkin," which refers specifically to the unisexual male flowers of the tree, as well as "osier," a word that describes the long, flexible sprigs of the plant often used in basket-making. Other related terms include "sallow," a type of willow tree often grown for its ornamental value, and "pussy willow," which refers to the soft, velvety buds that adorn many varieties of willow in the early spring.