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Related to Lunar libration: Lunar orbit, Libration in latitude


A very slow oscillation, real or apparent, of a satellite as viewed from the larger celestial body around which it revolves.

[Latin lībrātiō, lībrātiōn-, oscillation, from lībrātus, past participle of lībrāre, to balance, from lībra, balance.]

li′brate′ (lī′brāt′) v.
li·bra′tion·al adj.
li′bra·to′ry (-brə-tôr′ē) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. the act or an instance of oscillating
2. (Astronomy) 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
[C17: from Latin librātus, from librāre to balance]
liˈbrational adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(laɪˈbreɪ ʃən)

a real or apparent oscillatory motion, esp. of the moon.
[1595–1605; < Latin lībrātiō act of leveling = lībrā(re) to level, balance, derivative of lībra pair of scales + -tiō -tion]
li•bra′tion•al, adj.
li′bra•to`ry (-brəˌtɔr i, -ˌtoʊr i) adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.libration - (astronomy) a real or apparent slow oscillation of a moon or satellite; "the libration of the moon"
astronomy, uranology - the branch of physics that studies celestial bodies and the universe as a whole
variation - (astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earth's moon)
oscillation - the process of oscillating between states
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Fred Espenak, though justifiably famous for his eclipse-chasing skills, also provides daily data on lunar libration in tabular form (and much, much more) at his website.
They survey thousands of trajectories for transferring spacecraft between the Earth and various locations near the Moon, including lunar libration orbits, low-lunar orbits, and the lunar surface.
In this case relatively small modeled corrections were empirically derived at each band to account for the effects of lunar libration and small differences of phase angle in the SeaWiFS observations.
The Case of the Rotating Moon," the investigation of pre-Newtonian opinions on the question of whether the moon may have a sidereal rotation provides an interesting interpretation of Newton's work on lunar libration. Gabbey finds "continuities in the midst of change and revolution" (p.