What Is A Penumbral Shadow?

What Is A Penumbral Shadow? Penumbra, (from Latin paene, “almost”; umbra, “shadow”), in astronomy, the outer part of a conical shadow, cast by a celestial body, where the light from the Sun is partially blocked—as compared to the umbra (q.v.), the shadow’s darkest, central part, where the light is totally excluded. What is the difference