A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Geoffrey Kolbe
Date: 2021 Jun 15, 23:46 -0700
Sidereal is derived from the Latin word "sidereus" meaning of, or pertaining to, the stars
Stellar is derived from the Latin word "stellaris" meaning of, or pertaining to, the stars
The difference would appear to be one of context, or nuance, but I am no Latin expert to explain it!