An eclipse occurs when one celestial object moves into the shadow of another or passes between us and another object, blocking our view. The word comes from ancient Greek, meaning “to abandon” or “to leave out,” because during an eclipse, light seems to abandon the sky.

In a solar eclipse, the moon passes between Earth and the sun, casting a shadow on part of Earth and temporarily blocking sunlight. During a total solar eclipse, the moon covers the sun completely, and day turns briefly to twilight. People travel across continents to witness this rare spectacle. In a lunar eclipse, Earth passes between the sun and moon, and Earth's shadow falls across the moon's surface, sometimes turning it a dark red color.

Eclipses follow predictable patterns that ancient astronomers learned to calculate. The Maya could predict eclipses centuries in advance using careful observations and mathematics. Today, scientists know exactly when and where eclipses will occur decades into the future.

The word also describes being overshadowed by someone or something else. A talented student might feel eclipsed by a sibling who excels even more. A scientific discovery can eclipse earlier work, making previous achievements seem less important. When one thing eclipses another, it dominates attention so completely that the other fades from notice.