O Corrain and Maguire, who are the authority on names Irish, say: Aíbell (Old form): Aoibheall (modern form), pronounced eye-val (with slight y sound after the v) 'radiance, spark, fire)...according to some legends she is a supernatural lady who lives in the fairy mound of
Craig Liath (grey rock, I think) near Killaloe, County
Clare, and who appeared to
Brian Boru on the eve of the battle of Clontarf. The name is also borne by a couple of women in the Irish tales.
hth.