[In English] Full Moon: January is the Wolf Moon

The first full moon of the year will occur at dawn tomorrow, the 14th.

Q: What do you call a full moon?

A: It's a "full moon." Since it's the same as the Japanese term, that was too easy for a quiz. So, how would you say "the full moon is in Cancer"?

A full moon occurs in (the sign of) Cancer. If you want to say a full moon in Cancer, it's a full moon in (the sign of) Cancer.

The etymology of "moon" comes from the Old English "mōna," which traces back to the Proto-Germanic "*mēnô" and the Proto-Indo-European "*mḗh₁ns," meaning both moon and month. In ancient times, because the moon was used to measure the month, it is thought to be derived from "meh₁-," meaning to measure. The Japanese word for "one month" (hitotsuki) also comes from the moon's cycle of approximately 29.5 days, so it is the same in both Japanese and English that the celestial moon and the calendar month share the same word (or origin) because the phases of the moon are used to measure time.

When the moon is growing, it is "waxing," and when it is shrinking, it is "waning." We use it like,
The moon is waning this week.
The phrase
wax and wane is an idiom meaning to wax and wane, to rise and fall, or to increase and decrease, meaning.

Each month's full moon has multiple names, with expressions coming from Native Americans, the colonial era, or even brought over from Europe. The January full moon is called the "Wolf Moon," and it is said to be because the howling of wolves is often heard during this time; it feels like an English almanac using the moon. It is fun to gain new knowledge while feeling grateful that words observing nature, regardless of East or West, have been passed down through generations.

By the way, the moon refers to the celestial body we see from Earth, so

it takes the definite article "the", but when referring to a full moon, for example, it represents a specific moon (at a specific date and time) that presents a different appearance, so it becomes a + adjective + moon. This is the same as how the sky is "the sky," but a clear sky is "a sunny sky."

Furthermore, since it also means a satellite (moon) of a planet,

Jupiter has 95 moons with confirmed orbits.
Jupiter has 95 moons with confirmed orbits.

It can also be used in the plural form like this.