Rashi on Exodus 2:16/רש"י על שמות ב׳:ט״ז

1ולכהן מדין THE PRIEST OF MIDIAN — כהן signifies the chief amongst them (see Targ. Onkelos and Mekhilta יתרו); he had abandoned the idol-worship to which they were addicted and they banished him, driving him away from them (Exodus Rabbah 1:32).

2את הרהטים THE GUTTERS — the troughs for the currents of water which are excavated in the ground.