• synonyms

ephemeris second

See more synonyms for ephemeris second on Thesaurus.com
noun Astronomy.
  1. the unit of ephemeris time, defined as a precise fraction of the length of the tropical year 1900.
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Origin of ephemeris second

First recorded in 1965–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018