libration Meaning, Definition & Usage

  1. noun (astronomy) a real or apparent slow oscillation of a moon or satellite
    • the libration of the moon

WordNet

Li*bra"tion noun
Etymology
L. libratio: cf. F. libration.
Definitions
  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.

Webster 1913