What is the significance of the fact that here the Tzidonim called Chermon 'Siryon' and the Emori, 'S'nir', whereas later (in 4:48), the Torah refers to it as 'Si'on'?
Rashi: It teaches us that all different nationalities boasted that they owned a part of Eretz Yisrael 1 by claiming that its real name was the one by which they called it. 2
Ramban: The current Pasuk is describing the names that the Tzidonim 3 (the original residents of Har Chermon) and the Emori (the current residents) attached to Har Chermon. 4
Oznayim la'Torah: The northern section of the Chermon belonged to the Tzidonim, 5 who called their section - or perhaps the whole monntain - 'Siryon', and the southern section, to the Emori - which Yisrael captured, and which similarly, the Emori called 'S'nir'. 'Si'on', a section on top of the mountain that was permanently snow-capped, was Hefker and was also taken over by Yisrael.
Targum Yonasan: The Tzidonim called it 'Siryon' - because due to the large volume of fruit that grew on it, it tended to rot, 6 and the Emori, "S'nir" - because it was snow-capped all the year round.
Chulin, 60b #1: They are the name of mountains, and the Torah is teaching us that every nation went and built a large town for themselves and named it after the mountains of Yisrael - and we see from here the importanced they attached even to the mountains of Yisrael.
Chulin, 60b #2: "S'nir" and "Siryon" are names of maintains in Eretz Yisrael - and we see from here how various nations built for themselves large cities, which they named after the mountains of Eretz Yisrael - to teach us that even the mountais of Eretz Yisrael were dear to them. 7
Rashi (citing Targum Onkelos) and Ramban (citing the Sifri): "S'nir" actually means snow - bearing in mind that the Chermon is snow-capped all the year round. In fact, it seems that the other names are also corruptions of "S'nir" - See Ramban, and that the word for 'snow' in many modern languages - including English - is similar to it.
Ramban: In fact, 'Chermon is a nickname by which it was called because, due to the extreme cold, people tend to avoid going there - as if it was in Cheirem.
Ramban: Who was the B'chor of Cana'an (See Bereishis 10:15).
See Oznayim la'Torah.
See Na'ar Yonasan.
See Torah Temimah, note 1.
