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; and it was situated in Chevron, so called because he (Mamrei) attached himself to Hashem.
What is the significance of the fact that Avram settled down in Kiryas Arba (in Chevron)?
Rashi (in 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 S'dom twenty-five years later. 1
See Rashi (loc. cit.) at length.
How long did Avram reside in Chevron?
Rashi (Bereishis 21:34: Twenty-five years, beginning from thebyear that he arrived from Charan. 1
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).