This is the 8954th most frequent Japanese word.
水瓶座
Aquarius (the zodiac sign).
The word '水瓶座' (Aquarius) is used here to indicate the astrological sign of a person.
彼女は水瓶座です。
She is an Aquarius.
In this sentence, '水瓶座' represents the group of individuals whose astrological sign is Aquarius within the context of a horoscope forecast.
今日の占いによると、水瓶座の人は幸運な日になります。
According to today's horoscope, people under Aquarius will have a fortunate day.
Here, '水瓶座' is used to describe the characteristics typically associated with the Aquarius astrological sign.