Definitions
1.NounAn alignment of astronomical objects whereby one object comes between the observer (or notional observer) and another object, thus obscuring the latter.
2.NounEspecially, an alignment whereby a planetary object (for example, the Moon) comes between the Sun and another planetary object (for example, the Earth), resulting in a shadow being cast by the middle planetary object onto the other planetary object.
3.NounA seasonal state of plumage in some birds, notably ducks, adopted temporarily after the breeding season and characterised by a dull and scruffy appearance.
4.NounObscurity, decline, downfall.
5.VerbOf astronomical or atmospheric bodies, to cause an eclipse."The Moon eclipsed the Sun."
6.VerbTo overshadow; to be better or more noticeable than.
7.VerbTo undergo eclipsis.