libration

[ lahy-brey-shuh n ]

/ laɪˈbreɪ ʃən /

noun Astronomy.

a real or apparent oscillatory motion, especially of the moon.

Nearby words

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. 2019

Examples from the Web for libration

For other worlds, we usually have to rely on other data: fluctuations in gravity, or the gentle rocking motion known as libration.
Saturn’s Death Star Look-Alike|Matthew R. Francis|October 19, 2014|DAILY BEAST
The authors of the new study used data from the Cassini probe orbiting Saturn to measure the libration of Mimas.
Saturn’s Death Star Look-Alike|Matthew R. Francis|October 19, 2014|DAILY BEAST
The one on the left illustrates the manner in which the libration in longitude is made apparent.
Scientific American Supplement, No. 447, July 26, 1884|Various
A list of some of the principal astronomical researches of Lagrange and Laplace:—Libration of the moon.
Pioneers of Science|Oliver Lodge

The admirable memoir of Lagrange upon the libration of the moon seemed to have exhausted the subject.
Biographies of Distinguished Scientific Men|Francois Arago
We'd show enough, however, to make it damned impressive, and explain it by libration of the satellite.
Question of Comfort|Les Collins
The last of Galileo's great astronomical discoveries related to the libration of the moon.
Great Astronomers|R. S. Ball

British Dictionary definitions for libration

libration

/ (laɪˈbreɪʃən) /

noun

the act or an instance of oscillating

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

Derived Formslibrational, adjective

Word Origin for libration

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