An Etymological Dictionary of the German Language/Annotated/Petersilie
Petersilie, feminine, ‘parsley,’ from Middle High German pêtersil, masculine, pêtersilje, masculine, Old High German pêtarsile; borrowed from Middle Latin petrosilium (Greek πετροσέλινον), ‘parsley.’ In the Upper German dialects a shortened form is found, Peterli, Peterle (Peterling).