When many Greek immigrants came to the U.S. at Ellis Island or wherever else they came to, they shortened their names. Pappas means priest. People with this name are descendants of priests. (In the Greek Orthodox church, one can become a priest if married. Once ordained, however, one may not marry. A married priest nay not rise higher in the church hierarchy.) The surname of a priest's family was formerly changed to "Papa" plus the priest's first name, often in the genitive (possessive) case. Examples are Papantonis and Papastavrou. This then is often shortened to "Pappas."