time based upon the rotation of the earth with respect to the distant stars, the sidereal day being the unit of measurement
See also sidereal day
sidereal time in American English
1.
time measured by the sidereal day: it is divided into the sidereal hour (1⁄24 of a sidereal day), the sidereal minute (1⁄60 of a sidereal hour), and the sidereal second (1⁄60 of a sidereal minute)