astronomy A real or apparent slow oscillation of a moon or satellite.

Roget 314: oscillation; vibration, libration; motion of a pendulum; nutation; undulation; pulsation; pulse.    alternation; coming and going etc. v.; ebb and flow, flux and reflux, ups and down.    fluctuation; vacillation etc. (irresolution) 605.    wave, vibratiuncle^†, swing, beat, shake, wag, seesaw, dance, lurch, dodge; logan^†, loggan^†, rocking-stone, vibroscope^†.    ... show more

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