SYNONYMS | WORD ORIGIN noun . Astronomy the point on the celestial sphere directly beneath a given position or observer and diametrically opposite the zenith. . Astrology the point of a horoscope opposite the midheaven: the cusp of the fourth house. the lowest point; point of greatest adversity or despair. Origin of nadir 1350–1400; Middle English ≪ Arabic naẓīr over against, opposite to (the zenith) Related forms na·dir·al, adjective
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for nadiral noun the point on the celestial sphere directly below an observer and diametrically opposite the zenith the lowest or deepest point; depths the nadir of despair Word Origin for nadir
C14: from Old French, from Arabic
nazīr as-samt, literally: opposite the zenith
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for nadiral n.
late 14c., in astronomical sense, from Medieval Latin
nadir, from Arabic nazir "opposite to," in nazir as-samt, literally "opposite of the zenith," from nazir "opposite" + as-samt "zenith" (see zenith). Transferred sense of "lowest point (of anything)" is first recorded 1793.
Online Etymology Dictionary, © 2010 Douglas Harper
The point on the celestial sphere that is directly below the observer (90 degrees below the celestial horizon). Compare zenith.
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.