new moon

noun

1

: the moon's phase when it is in conjunction with the sun so that its dark side is toward the earth

also : the thin crescent moon seen shortly after sunset for a few days after the actual occurrence of the new moon phase

2

: the beginning of each Jewish month marked by a special liturgy

Examples of new moon in a Sentence

Recent Examples on the Web

Each partial solar eclipse takes place during the monthly new moon phase, when the lunar disk passes between Earth and sun, occulting (or hiding) its light while stopping short of perfectly blocking out its surface. —Anthony Wood, Space.com, 21 Sep. 2025

On Sunday, there will be a new moon. —Julia Gomez, USA Today, 21 Sep. 2025

Prepare for big changes as September's upcoming new moon doubles as a solar eclipse. —Victoria Edel, PEOPLE, 20 Sep. 2025

In the wake of a partial solar eclipse in North America on March 29, skywatchers in New Zealand, Antarctica and the South Pacific who get up early will see up to 86% of the sun’s disk blocked by a new moon — a rare event. —Jamie Carter, Forbes.com, 18 Sep. 2025

Word History

First Known Use

before the 12th century, in the meaning defined at sense 1

Rhymes for new moon

• attune
• baboon
• balloon
• bassoon
• buffoon
• cartoon
• cocoon
• festoon
• gaboon
• harpoon
• immune
• impugn

Kids Definition

new moon

noun

: the moon's phase when its dark side is toward the earth

also : the thin curved outline of the moon seen shortly after sunset for a few days after the actual occurrence of the new moon phase