Merels (also called Nine Men‘s Morris) comprises a family of traditional board games with ancient roots. Between medieval and modern times, merels saw an interesting onomasiological shift: Several European languages took up a new name for the game. This new name is sometimes claimed to have originated in German, but the details surrounding this naming practice are still unclear. There are mainly two German groups of names for this game, the older names based on the number 9 (Neunstein, Neunten Stein, Neunermal etc.) and the younger based on the German word for “mill” (Mühle, Mühlspiel, Mühleziehen etc.). Relying on philological evidence (partly pulled from lexicographical data) this paper outlines the evolution of German terms for merels, focusing on the naming practices from the 15th to 17th century. Possible motivations of the name Mühle are discussed.