say it: lahy-BRAY-shuhn
libration is a noun meaning "(astronomy) a real or apparent slow oscillation of a moon or satellite". It carries one recorded sense.
(astronomy) a real or apparent slow oscillation of a moon or satellite
“the libration of the moon”
astronomy
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for libration come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.