Morgan's roots are genuinely contested, with proposed Welsh meanings including "sea-born" and "bright circle," and further complexity added by its long association with a shape-shifting enchantress in Arthurian legend. Across the competing readings runs a thread of something elemental and hard to pin down -- fluid rather than fixed.
There will be some impediment about that part of the body represented by that sign which was afflicted at birth. - William Lilly (1602.-1681.)