Ava's origin is genuinely debated, with roots traced variously to the Latin avis ("bird") and Hebrew associations with life or breath. Both threads point toward something airy and animating rather than heavy or fixed. The name is often understood as evoking lightness and vitality, a sense of motion rather than permanence.
Every beginning when the Moon shall be joined to a Retrograde planet will soon be destroyed, and if she shall be otherwise impedited, the mischief will happen the sooner. - William Lilly (1602.-1681.)