ephemeris second
noun Astronomy.
the unit of ephemeris time, defined as a precise fraction of the length of the tropical year 1900.
Origin of ephemeris second
First recorded in 1965–70
Words nearby ephemeris second
ephemera,
ephemeral,
ephemerality,
ephemerid,
ephemeris,
ephemeris second,
ephemeris time,
ephemeron,
ephemeropteran,
ephemerous,
ephes.