Leo is the Latin word for lion, used as a name for its direct associations with courage and boldness rather than any hidden meaning. It's a name that wears its symbolism plainly -- strength on the surface, not something to be uncovered through etymology.
When true genitures exactly taken in accidents prove false or absurd, and not agreeable to the things signifies, they are to be accounted monstrous, and are to be avoided as anatomists do monstrous bodies in their dissections; for they overthrow Art. - Cardan Girolamo (1501-1576)