Rashi on Leviticus 3:9/רש"י על ויקרא ג׳:ט׳

1חלבו means: the choicest part in it; and what is this? The whole fat-tail.

2לעמת הָעֶצָה — i. e. above the kidneys which give counsel (עֵצָה) (cf. Rashi on Exodus 29:22 and Note thereon).