Visible, a.
Etymology: [L. visibilis, fr. videre, visum, to see: cf. F. visible. See Vision.]
1. Perceivable by the eye; capable of being seen; perceptible; in view; as, a visible star; the least spot is visible on white paper. Maker of heaven and earth, and of all things visible and invisible. Bk. of Com. Prayer. Virtue made visible in outward grace. Young.
2. Noticeable; apparent; open; conspicuous. Shak. The factions at court were greater, or more visible, than before. Clarendon. Visible church (Theol.), the apparent church of Christ on earth; the whole body of professed believers in Christ, as contradistinguished from the invisible, or real, church, consisting of sanctified persons. -- Visible horizon. Same as Apparent horizon, under Apparent. -- Vis"i*ble*ness, n. -- Vis"i*bly, adv.
Shades of meaning
Fernald has no entry of its own for visible; he lists it under evident, physical.
Where he writes about it:
Visible applies to all that can be perceived by the sense of sight, whether the noonday sun, a ship on the horizon, or a microscopic object. — from evident
Discernible applies to that which is dimly or faintly visible, requiring strain and effort in order to be seen; as, the ship was discernible through the mist. — from evident