new moon

American  

noun

1. the moon either when in conjunction with the sun or soon after, being either invisible or visible only as a slender crescent.

2. the phase of the moon at this time.

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new moon British  

noun

1. the moon when it appears as a narrow waxing crescent

2. the time at which this occurs

3. astronomy one of the four principal phases of the moon, occurring when it lies between the earth and the sun

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new moon Scientific  

/ no̅o̅ /

1. The phase of the Moon that occurs when it passes between Earth and the Sun, making it either invisible or visible only as a thin crescent at sunset.

2. See more at moon Compare full moon

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Etymology

Origin of new moon

before 1000; Middle English; Old English

Compare meaning

How does new-moon compare to similar and commonly confused words? Explore the most common comparisons:

• new moon vs. full moon

Example Sentences

With the event coinciding with a new moon for the first time since 2018, you just need to find a dark spot away from city lights and enjoy the display.

From The Wall Street Journal • Mar. 27, 2026

Moon spotters were passing their skills to the next generation as Muslims waited for a sighting of the new moon to celebrate Eid.

From BBC • Mar. 20, 2026

This is thanks to the new moon, which cuts down on natural light — though unfortunately not L.A.’s widespread light pollution.

From Los Angeles Times • Oct. 18, 2025

To find out, the group systematically observed the worms' daily activities when there was a new moon.

From Science Daily • Apr. 15, 2024

Sí, there was one, not far from the new moon, the very one she had pointed out as Papá’s star in Ensenada just last month.

From "Lupita Mañana" by Patricia Beatty