[name] Prosser is an English-language surname, derived from a Welsh-language patronym. ==Origin== The English-language surname Prosser is considered to be a Welsh surname. The name originated as an Anglicisation of the Welsh-language ap Rhosier, or ap Rosser, both meaning son of Roger. The English-language personal name Roger is derived fro... Found on http://en.wikipedia.org/wiki/Prosser_(name)