libration

noun

li·​bra·​tion lī-ˈbrā-shən How to pronounce libration (audio)
: an oscillation in the apparent aspect of a secondary body (such as a planet or a satellite) as seen from the primary object around which it revolves
librational adjective
libratory adjective

Examples of libration in a Sentence

Recent Examples on the Web
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But each full moon varies month to month, due to its slightly shifting orientation, known as libration, and the changing distance from Earth in its elliptical orbit. Taylor Nicioli, CNN, 19 July 2024 Based on the new model and Enceladus' libration — relatively large back-and-forth swings during its orbit — the data indicate the moon's ocean is only a few miles beneath the surface. Nathaniel Scharping, Discover Magazine, 4 Oct. 2016 The discovery pivots on the detection of a curious libration—a wobble—in the rotation of Mimas. Jamie Carter, Forbes, 19 Jan. 2022

Word History

Etymology

Latin libration-, libratio, from librare to balance, from libra scales

First Known Use

1667, in the meaning defined above

Time Traveler
The first known use of libration was in 1667

Dictionary Entries Near libration

Cite this Entry

“Libration.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/libration. Accessed 21 Nov. 2024.

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