The word “moon” is not always written with a capital letter. We explain in which cases it is necessary to use one and when it is written with a lowercase letter. You will no longer be able to make a mistake!
“Lune” is one of those words that are both proper and common nouns. It is therefore necessary to use a capital letter or a lowercase letter depending on the case, but it is not always easy to know when to opt for one or the other of these ways of writing this word. We explain how to write “Lune/lune” depending on the situation.
The proper noun Moon refers to the Earth’s natural satellite, and it is only in this case that it is necessary to use a capital letter. Thus, we would write “Neil Armstrong walked on the Moon”, “350,000 km separate the Earth and the Moon” or “NASA is going to send a rocket to circle the Moon” because we are then talking about the celestial body itself.
Conversely, the word moon becomes a common noun and therefore does not take a capital letter in all other cases, when it is used in a figurative expression like “full moon night”, “crescent moon”, “honeymoon”, “to be in the moon”, “the glow of the moon”, “to pick up the moon”, “to ask for the moon”…
It is good to know that this rule also applies to the Sun (“the Sun is the biggest star that exists” / “you have to be careful of sunburn”), but also to the Earth (“humans live on the Earth” / “have your feet on the ground”), to the stars (“the Shepherd’s Star” / “look at the stars”), and to all nouns and adjectives directly designating planets, stars or even constellations.
The same goes for the words “universe”, “cosmos” or “galaxy”. For example, we would say “our Galaxy” but “the Andromeda galaxy”. To know whether or not to capitalize these words, we must therefore ask ourselves whether we are referring directly to the planet, the star, etc., or whether we are using this word in the common sense. In the first case, we use a capital letter, and in the second a lowercase letter.