| 释义 |
li·bra·tion
\līˈbrāshən\ noun
(-s)
Etymology: Latin libration-, libratio, from libratus + -ion-, -io -ion
1. : the action or state of librating
2. obsolete : the act or process of weighing
3. : an oscillation in the apparent aspect of a secondary body (as a planet or a satellite) as seen from the primary object around which it revolves caused by the inclination of its axis of rotation, variations in its orbital speed, real irregularities in its rotation, or changes in the observer's position on the primary body — see libration of the moon |