In Old Norse, áss (or ǫ́ss, ás, plural æsir, feminine ásynja, feminine plural ásynjur) is the term denoting one of the principal groups of gods of the pantheon of Norse paganism. They include many of the major figures, such as Odin, Frigg, Thor, Baldr and Tyr. They are one of the two groups of gods, the other being the Vanir.