名詞 nadir:

1. an extreme state of adversity; the lowest point of anything
   同義詞：low-water mark
2. the point below the observer that is directly opposite the zenith on the imaginary sphere against which celestial bodies appear to be projected

na.dir

n.（名詞）
Astronomy A point on the celestial sphere directly below the observer, diametrically opposite the zenith.
【天文學(xué)】 天底：天球上，在觀測者垂直向下的一點，與天頂完全相對
The lowest point:
最低點：
例句：
the nadir of their fortunes.
他們最不景氣的時候

來源：
Middle English
中古英語
from Medieval Latin
源自 中世紀(jì)拉丁語
from Arabic naYor (as-samt) [opposite (the zenith)]
源自 阿拉伯語 naYor (as-samt) [相反的（天頂）]