The word "bunion" comes from the Middle English word "boune," which means "swelling." The word "boune" was derived from the Old English word "buna," which also means "swelling." The word "bunion" was first used in the 16th century to describe a lump or protrusion on the big toe joint.
The medical term for a bunion is hallux valgus, which is Latin for "turned out big toe." This refers to the condition in which the big toe angles towards the second toe, which causes the prominence or "bump" on the side of the big toe joint.
It's worth to mention that the condition has been known since ancient times and there are several references in the medical literature of ancient cultures, such as the Egyptians, Greeks and Romans, to a condition similar to the modern bunion, which was also known as "hallux valgus".