- 1[countable] an occasion when the moon passes between the earth and the sun so that you cannot see all or part of the sun for a time; an occasion when the earth passes between the moon and the sun so that you cannot see all or part of the moon for a time an eclipse of the sun/moon a total/partial eclipse
- 2[singular, uncountable] a loss of importance, power, etc. especially because someone or something else has become more important, powerful, etc. The election result marked the eclipse of the right wing. Her work was in eclipse for most of the 20th century.