Dictionary

An alignment of astronomical objects whereby one object comes between the observer (or notional observer) and another object, thus obscuring the latter.

Especially, 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.

A seasonal state of plumage in some birds, notably ducks, adopted temporarily after the breeding season and characterised by a dull and scruffy appearance.

Obscurity, decline, downfall

Of astronomical bodies, to cause an eclipse.

Example: The Moon eclipsed the Sun.

To overshadow; to be better or more noticeable than.

(Irish grammar) To undergo eclipsis.