A hybrid eclipse is one in which it is a total eclipse in some places and an annular eclipse is seen in other places.
As you may know, a total eclipse is one in which the moon completely covers the disc of the Sun; this allows the solar corona to be seen. Usually the central disc of the Sun is so bright that the corona cannot be seen. An annular eclipse is one in which the Moon is not quite "large" enough to completely block out the Sun - instead, a ring of the Sun's central disc can be seen around the Moon. This ring is too bright for the corona to be seen. Photos of both eclipse types appear below.
Annular Eclipse (credit: Fred Espenak at www.mreclipse.com):
Total Eclipse (credit: Fred Espenak at www.mreclipse.com):
The type of eclipse is determined by the geometry of the Sun, Earth, and Moon. Since the Sun and Moon are not constantly at the same distance from the Earth, their apparent sizes will differ. When the Moon is closer to the Earth it appears larger, and when the Sun is farther away it will appear smaller. For this particular eclipse, the geometry is such that the western part of the eclipse's center line will see an annular eclipse, but the rest will have a total eclipse.