Noah Webster
Sidereal
SID'ERAL, SIDE'REAL, adjective [Latin sideralis, from sidus, a star.]
1. Pertaining to a star or stars; astral; as sideral light.
2. Containing stars; starry; as SIDEREAL regions. SIDEREAL year, in astronomy, the period in which the fixed stars apparently complete a revolution and come to the same point in the heavens.