A Hemi engine has a hemispherical dome, which was a new design that increased efficiency and power output over others, in 1901.
Chrysler popularized the term for their engines in the 1950’s, and the name has a positive image in some circles because Chrysler-built Hemi engines were used in WW2 fighter planes and NASCAR racecars.
Nooo, it’s where the baby Jesus’s grow!