Is “Egyptian Year” the same as a modern sidereal year?

Question

Copernicus uses the term "Egyptian Year" throughout his discussions of the movements of the Earth, and of his and other models of the movements of the planets; but is unclear from his text, or from the general definitions I've found, what this corresponds to in modern astronomical terms.

What, precisely, is an "Egyptian Year"? Is it identical with a modern sidereal year; if not, what are the correct conversions between the two?

Answer 1

Egyptian year is not the same as sidereal year. Egyptian year is exactly 365 days, whereas sidereal year is approximately 365.256 days.