The Collaborative International Dictionary of English v.0.48:
AEsir \[AE]"sir\, n. pl. [Icel., pl. of [=a]ss god.] In the old Norse mythology, the gods Odin, Thor, Loki, Balder, Frigg, and the others. Their home was called Asgard. [Webster 1913 Suppl.] EsopianWordNet (r) 3.0 (2006):
Aesir n 1: (Norse mythology) the chief race of gods living at Asgard