Main Entry: na·dir

Pronunciation: \ˈnā-ˌdir, ˈnā-dər\

Function: noun

Etymology: Middle English, from Middle French, from Arabic naḍhīr opposite

Date: 15th century

1 : the point of the celestial sphere that is directly opposite the zenith and vertically downward from the observer
2 : the lowest point

[nadir illustration]