Jessica = "the Lord's gift".
Pierce = a form of Peter. Peter of course comes from the Greek petros, meaning "rock".
However, "peter" is also a slang term for the penis. Therefore jessicapierce could legitimately be considered God's gift to men, or more literally, "the Lord's gift to the penis".
Note: the Oxford English Dictionary's second entry for "peter" defines it as "The cry of various tits." I don't even want to get into the implications of that one...