new moon; invisible moon
Rare, poetic term for the new moon, specifically the phase when the moon is completely invisible. More commonly expressed as 新月 (しんげつ) or 朔 (さく).
On the night of the new moon, the sky is pitch black and the stars are clearly visible.
Common modern term for the new moon; 三十日月 is a rare, literary alternative.
Technical or classical term for the new moon; 三十日月 is more poetic and less used.
Compound of 三十日 (みそか, 'last day of the month') and 月 (つき, 'moon'), referring to the moon on the thirtieth day of the lunar month, when it is invisible. The exact historical derivation is uncertain.