* Syzygy: This is the most general term and simply refers to the alignment of any three celestial bodies in a straight line. It can apply to the Sun, Earth, and Moon, but also other configurations like the Sun, Earth, and a planet.
* Solar eclipse: This occurs when the Moon passes between the Sun and Earth, blocking the Sun's light. This requires a perfect alignment of the Sun, Moon, and Earth.
* Lunar eclipse: This occurs when the Earth passes between the Sun and the Moon, casting a shadow on the Moon. Again, this requires a precise alignment of the Sun, Earth, and Moon.
* New Moon: This is the phase of the Moon when it is between the Sun and the Earth and we cannot see it. This alignment is not perfect, but close enough that the Moon is in the Sun's shadow.
So, the specific term depends on what is happening during the alignment.
