What exactly, does the word "Eilonei (Mamrei)" mean?
Targum Onkelus and Targum Yonasan: It means the plains of (Mamrei).
Rashi: It is the name of the plain belonging to Mamrei (Avraham's friend).
What is the significance of Avraham's friend 'Mamrei' and of the town Chevron?
Rashi (in the initial print): Avraham's friend was called 'Mamrei' because he rebelled against the idolatry that his contemporaries worshipped; whereas Chevron was so-called because he (Mamrei) attached himself to HaSh-m.
What is the significance of the fact that Avraham settled down in Kiryas Arba (in Chevron)?
Rashi (to Bereishis 21:34): This took place in the same year that he arrived from Charan. Until now, he had traveled from one place to another (including spending three months in Egypt), and this is the first time that he settled permanently in one place. He remained there until the overturning of Sedom twenty-five years later. 1
See Rashi (loc. cit.) at length.
QUESTIONS ON RASHI
Rashi writes: "Mamrei is the name of a person." But perhaps it is the name of the location?
Gur Aryeh: The location is known by other names. Our verse tells us that the name of the city is Chevron; and the name of the plain is Eilonei (Rashi to 14:6).