Uropygi is a scientific name for a group of arachnids commonly known as whip scorpions or vinegaroons. These arthropods are nocturnal predators that use their elongated pedipalps and whip-like tail for hunting and self-defence. While "uropygi" is the most common name for this group, there are other synonyms that are occasionally used. For example, Thelyphonida is an alternate name that refers to the similar-looking arachnid order that includes whip spiders. Another synonym is "amblypygi," which is another arachnid order that shares some similarities with uropygi such as the whip-like structures on the body. However, whip scorpions are distinct and unique creatures that have their own characteristics that make them fascinating to study and observe.