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.
Origin
before 1000;Middle English;Old English
Examples from the web for new moon
They cited references in the story that the day of the prophecy was a new moon, which would be true of an eclipse.
There would be no stillness of the moon or of the night except during the new moon phase.
Sleep in the light of a new moon and you may never wake up.
The new moon earlier in the week will ensure that the skies will be perfectly dark for the shower.
The new moon-when it is aligned with the sun-occurs on the same day, ensuring unusually high tides.
Look on some calendars and you should see the days when the new moon is to be seen.
British Dictionary definitions for new moon
new moon
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
new moon in Science
new moon
(n) 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. See more at moon. Compare full moon.