ON DAF TEYS ZAYIN OMUD BEYS THE GEMARA SPEAKS ABOUT THE INYAN BICHLALL OF APPOINTING DAYANIM AND THE GEMARA SAYS THAT BEFORE YOU COME ONTO THE MEKOR IN PARSHAS SHOFTIM YOU FIND THAT YISRO IN PARSHAS YISRO ALREADY SUGGESTS THE IDEA TO MOISHE RABEINU AND RASHI [I AM SORRY I DO NOT HAVE A GEMORO IN FRONT OF ME TO QUOTE THE EXACT D.H.]SAYS A LOSHON OF SHOFET VEDAYAN . SO MY SHEILAH IS WHAT IS THE ACTUAL CHILUK BETWEEN THE 2 AND MEMEILA WHY DID RASHI HAVE TO USE BOTH LESHOINOS I ONCE HEARD A CHILUK BUT I DONT HAVE A MEKOR AND NOT SURE HOW CORRECT IT IS THAT A SHOFET IS A JUDGE THAT WE NORMALLY UNDERSTAND BUT DAYAN MEANS TO GIVE SOMEONE ELSE THE YECHOILES TO BE A MOIREH HOROOAH IE REUVEN IS A DAYAN BECAUSE HE CAN MAKE SHIMON A SHOFET BY GIVING HIM SEMICHAH SO THAT SHIMON CAN BE MIREH HOROOAH KOL TUV BORUCH KAHAN
BORUCH KAHAN , LONDON U.K.
Good question. To preface my answer, I would first like to explain the first Rashi in Parshas Shoftim. Rashi says "Shoftim - Dayanim ha'Poskim Es ha'Din" - "judges who Pasken the Halachah." The commentaries ask, why did Rashi have to tell us that judges Pasken? The Be'air ba'Sadeh answers that being that Shofet is from the term "Mishpat," one would think that they also give punishment, not just rule that people should receive punishments. Rashi therefore says that they merely Pasken, as opposed to the "Shoter" who actually metes out the punishment ruled on by Beis Din.
It is possible that "Mishpat" meaning strict punishment is also the key to understanding our Rashi. As we said above, a Shofet does not mete out punishment himself. However, he does rule that someone must receive death, lashes, etc. It is possible that the connotation of "Shofet" is more of a judge who rules on punishments, while the connotation of "Dayan" is one who rules on monetary matters. Of course, if the Mishna or Gemara specifies that a certain number of Dayanim is needed for a certain punishment, it is clear that this is someone who also deals with punishments. The word Shofet is not necessary. However, Rashi is discussing the novel idea that Moshe Rabeinu was considered like the Sanhedrin ha'Gadol. Accordingly, Rashi possibly wants to stress that Moshe was considered like the Sanhedrin ha'Gadol both regarding the connotation of "Shofet" meaning matters of punishment, and matters of money implied by "Dayan."
All the best,