• synonyms


[lahy-brey-shuh n]
noun Astronomy.
  1. a real or apparent oscillatory motion, especially of the moon.
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Origin of libration

1595–1605; < Latin lībrātiōn- (stem of lībrātiō) a balancing. See librate, -ion
Related formsli·bra·tion·al, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for libration

Contemporary Examples

Historical Examples

  • A list of some of the principal astronomical researches of Lagrange and Laplace:—Libration of the moon.

  • The one on the left illustrates the manner in which the libration in longitude is made apparent.

  • The last of Galileo's great astronomical discoveries related to the libration of the moon.

  • One more astronomical discovery also he was to make—that of the moon's libration.

  • We'd show enough, however, to make it damned impressive, and explain it by libration of the satellite.

British Dictionary definitions for libration


  1. the act or an instance of oscillating
  2. a real or apparent oscillation of the moon enabling approximately 59 per cent of the surface to be visible from the earth over a period of time
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Derived Formslibrational, adjective

Word Origin

C17: from Latin librātus, from librāre to balance
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