An Etymological Dictionary of Astronomy and Astrophysics

The solar day on Mars, which has a mean period of 24 hours 39 minutes 35.244 seconds (based on SI units), about 2.7% longer than Earth’s solar day. The Martian sidereal day, as measured with respect to the fixed stars, is 24h 37m 22.663s, as compared with 23h 56m 04.0905s for Earth.

See also: Sol, from L. sol “sun,” cognate with Pers. hur, → Sun.