waxing and waning (of the moon)
Astronomical term for the moon's phases; used in both scientific and everyday contexts.
The moon's waxing and waning repeats in a cycle of about 29.5 days.
Standard kanji spelling for the waxing and waning of the moon.
Rarely used kanji form.
Compound of 満ち (michi, 'to become full') + 欠け (kake, 'to wane, to be missing'), from the verbs 満ちる and 欠ける.