Rashi on Genesis 13:11/רש"י על בראשית י״ג:י״א

1ככר The word means “a plain” as the Targum translates it.

2מקדם FROM THE EAST — He removed from Abram and went westward of Abram — consequently he travelled from the East to the West. A Midrashic explanation is: He wandered away from the Originator (מקדמונו) of the Universe, saying, “I want neither Abram nor his God” (Genesis Rabbah 41:7).