sidereal day

noun

, Astronomy.

1. the interval between two successive passages of the vernal equinox over the meridian, being about four minutes shorter than a mean solar day.

sidereal day

noun

1. See day

Word History and Origins

Origin of sidereal day¹

First recorded in 1785–95

Example Sentences

This 5th day is the sidereal day of the astronomers and is the basis of our time, so it is entitled to a little attention.

From Project Gutenberg