The Hebrew ebrah refers to a wing, pinion, or flight feather of a bird. It is closely related to eber (H83) and is used poetically to describe the wings of the eagle and God's protective care.
In Psalm 91:4, God's ebrah — His pinions, His great feathers — become a refuge for the one who trusts in Him. This is not mere poetry but covenantal promise: the Almighty shelters His people under His wings like a bird shelters its young. The imagery connects to the Hebrew word for "wing" also used for the corners of a garment — Boaz "spreading his wings" over Ruth (Ruth 3:9) mirrors the divine protection offered to all who take refuge in God.