The New Dictionary of Cultural Literacy, Third Edition. 2002.
eclipse
In astronomy, the blocking out of light from one object by the intervention of another object. The most dramatic eclipses visible from the Earth are eclipses of the sun (when sunlight is blocked by the moon) and eclipses of the moon (when sunlight on its way to the moon is blocked by the Earth).
The term eclipse is also used to refer to a general decline or temporary obscurity: After taking the title last year, the team has gone into an eclipse this season.