Another matter, “Yitro…heard.” He was called seven names:19Yeter, Yitro, Ḥovav, Reuel, Ḥever, Putiel, Keini. Yeter, when he was an idolater, as it is stated: “He returned to Yeter, his father-in-law” (Exodus 4:18). When he converted, a letter was added for him, just as it was for Abraham, and he was called Yitro. Alternatively, Yitro, because he added [yiter] one portion in the Torah, as it is stated: “You shall discern from all the people” (Exodus 18:21).20He recommended establishing a judicial system. Ḥovav, because he loved [ḥibev] the Torah, as it is written in the portion of: “Moses said to Ḥovav” (Numbers 10:29).21This verse is cited to prove that Yitro was called Ḥovav (Etz Yosef).
Yitro's Journey
Shemot Rabbah 27:8