si|de|re|al

si|de|re|al «sy DIHR ee uhl», adjective.

1. of or having to do with the stars or constellations: »

our sidereal system.

SYNONYM(S): astral, stellar.

2. measured by the apparent daily motion of the stars: »

A sidereal day is shorter than a mean solar day by 3 minutes and 56 seconds (Eric D. Carlson). A sidereal month—27¹/₃ days—is the time the moon takes to make one trip around the earth in relation to the stars (Eugene M. Shoemaker).

See also sidereal time. (Cf. ↑sidereal time)

╂[< Latin sīdereus astral (< sīdus, -eris star) + English -al¹]