What is another word for mean solar day?
Pronunciation: [mˈiːn sˈə͡ʊlə dˈe͡ɪ] (IPA) 
The term "mean solar day" refers to the average length of a day on the Earth. It is based on the solar day, which is the time it takes the Earth to rotate once on its axis, but averaged over the course of a year to account for the irregularities in the Earth's orbit. There are several synonyms for mean solar day, including civil day, average solar day, and standard time day. These terms are used interchangeably and refer to the same concept. While the length of a mean solar day varies slightly from day to day, it serves as a standard unit of time for many purposes, including determining the length of a year and setting time zones.
