Other forms: moons
The moon is the bright circle in the night sky that changes shape through the month. A full moon, the new moon, moonlight.
It goes through its phases in about 29 and a half days, which is where the month comes from. The same face always points at us, because it turns once for every orbit. It causes the tides. Note once in a blue moon, meaning rarely; over the moon, meaning delighted; and that other planets' moons are also called moons, so ours has to be capitalised to be specific.
1nounmoonThe bright body that orbits the earth and lights the night.
“The moon takes about 29 days to go round the phases.”
2nounnaturalA natural satellite of any planet.
“Jupiter has dozens of moons, and the largest is bigger than the planet Mercury.”
Too few real examples of this word to estimate which sense is commonest.
moon is a celestial body.
Old English mona goes back to a root probably meaning to measure — the moon was the first calendar. Month, measure and menstrual come from the same measuring.
Middle English
mone
English, today
moon
Built from
From Middle English mone. From Middle English mone, from Old English mōna (“moon”), from Proto-West Germanic mānō, from Proto-Germanic mēnô (“moon”), from Proto-Indo-European mḗh₁n̥s (“moon; month”), probably from meh₁- (“to measure”). 2
Etymology from Wiktionary, CC BY-SA