The term "primary quill" refers to the flight feathers at the tips of a bird's wings that provide the primary lift and thrust during flight. Some synonyms for the word "primary quill" are "flight feather," "pinion feather," "remige," "wing feather," or simply "primary." These feathers are critical for a bird's survival, as they enable efficient and sustained flight. The structure and arrangement of primary quills vary among different species of birds, depending on their wing shape and flight style. In some cases, these feathers may be brightly colored or have unique patterns, contributing to the bird's visual appeal.