Definition of libration in English:

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Pronunciation: /līˈbrāSHən/


An apparent or real oscillation of the moon, by which parts near the edge of the disc that are often not visible from the earth sometimes come into view.
Example sentences
  • Permanent settlements have been proposed for the Moon and Mars, as well as stable positions in space equidistant from both Earth and Moon called the Lagrangian libration points.
  • The topic was on the libration of the Moon, that is the motion of the Moon which causes the face that it presents to the Earth to oscillate causing small changes in the position of the lunar features.
  • He discovered the libration of the Moon and this gained him fame which led to his appointment as professor of economics and mathematics at Göttingen in 1751.



Pronunciation: /ˈlīˌbrāt/
Example sentences
  • Another Lagrangian-loving NASA satellite, known as Genesis, will librate around the Sun-Earth L1 point.
  • The comet currently librates around the ‘high’ 13: 15 mean motion resonance with Jupiter.
  • We have found that critical arguments librate around 0 degrees for several hundred thousand years.


Early 17th century (denoting an oscillating motion, or equilibrium): from Latin libratio(n-), from the verb librare, from libra 'a balance'.

For editors and proofreaders

Syllabification: li·bra·tion

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