Nadir is a word that is used as a noun and the meaning it conveys is that of the worst part of something or of a situation. The word is used in very formal English and people don't use the word usually in every day conversation. But in written English the word is quite common and you can find its use in any newspaper or a magazine. As we always believe that unless something is used in context it is hardly possible for a person to understand the meaning of the term well. Keeping in mind this very thought, given below a sentence that has used the word in context: The Company reached at its nadir in the year 2000 and finally it was declared bankrupt.