Etymology of the Latin word sciurus
the Late Latin word sciurus (squirrel)
derived from the Greek word skiouros, σκίουρος
derived from the Greek word oura, οὐρά (tail; a tail)
derived from the Proto-Indo-European root *ors- (tail)
derived from the Greek word skia, σκιά (shadow; 'shade' or a shadow (literally or figuratively (darkness of error or an adumbration)))
using the Greek suffix -morphe