[lahy-brey-shuh
n] 
| a real or apparent oscillatory motion, esp. of the moon. |
| li·bra·tion (lī-brā'shən) 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. |
