Antumbra
An antumbra marks the path of annularity in an annular eclipse. In an annular eclipse, the moon is not of sufficient size to completely cover the sun, and so its shadow is not long enough to reach the Earth and result in a total solar eclipse. At maximum eclipse, the moon is surrounded by a ring, or annulus, of light, and the location on Earth where the ring can be seen is also the location of the "negative shadow", or antumbra.