When the Sun, Moon, and Earth align, it's called a syzygy (pronounced siz-i-jee). This alignment can occur in a couple of ways:

* Solar Eclipse: The Moon is between the Sun and Earth, blocking the Sun's light and casting a shadow on Earth.

* Lunar Eclipse: The Earth is between the Sun and Moon, blocking the Sun's light from reaching the Moon and casting a shadow on it.

While syzygy refers specifically to the alignment of these three celestial bodies, it's often used interchangeably with these eclipses. However, it's important to remember that syzygy simply describes the alignment, while eclipses are specific events that occur due to this alignment.