libration
4 dictionary results for: Libration
Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This
li·bra·tion 
[lahy-brey-shuhn] Pronunciation Key
[lahy-brey-shuhn] Pronunciation Key –noun Astronomy.
| a real or apparent oscillatory motion, esp. of the moon. |
Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.
American Heritage Dictionary - Cite This Source - Share This
| li·bra·tion
(lī-brā'shən) Pronunciation Key
n. A very slow oscillation, real or apparent, of a satellite as viewed from the larger celestial body around which it revolves. [Latin lībrātio, lībrātiōn-, oscillation, from lībrātus, past participle of lībrāre, to balance, from lībra, balance.] li·bra'tion·al adj., li'bra·to'ry (-brə-tôr'ē, -tōr'ē) adj. |
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The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
WordNet - Cite This Source - Share This
| libration | |
noun | |
| (astronomy) a real or apparent slow oscillation of a moon or satellite; "the libration of the moon" |
WordNet® 3.0, © 2006 by Princeton University.
Webster's Revised Unabridged Dictionary - Cite This Source - Share This
Libration
Li*bra"tion\ (l[-i]*br[=a]"sh[u^]n), n. [L. libratio: cf. F. libration.]1. The act or state of librating. --Jer. Taylor. 2. (Astron.) A real or apparent libratory motion, like that of a balance before coming to rest. Libration of the moon, any one of those small periodical changes in the position of the moon's surface relatively to the earth, in consequence of which narrow portions at opposite limbs become visible or invisible alternately. It receives different names according to the manner in which it takes place; as: (a) Libration in longitude, that which, depending on the place of the moon in its elliptic orbit, causes small portions near the eastern and western borders alternately to appear and disappear each month. (b) Libration in latitude, that which depends on the varying position of the moon's axis in respect to the spectator, causing the alternate appearance and disappearance of either pole. (c) Diurnal or parallactic libration, that which brings into view on the upper limb, at rising and setting, some parts not in the average visible hemisphere.
Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
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