Leviticus 3:4

הכסלים — Flancs in O. F. — It speaks of the fat which is on (על) the kidneys being also on (על) the flanks because the fat that is upon the kidneys is, when the animal is living, on the uppermost part of the flanks, and they (the kidneys) are in a downward position. This is the fat which is under the loins — what are called lombles in O. F.; it is that white fat which is visible upon the upper part of the flanks, but on their lower part the flesh covers it, (and this latter portion of the fat is therefore not upon but under the flanks). היותרת is the protecting wall (membrane) over the liver which is called abris in O. F. In the Aramaic language it is called חצרא דכבדא the lobe of the liver. על הכבד — This must mean that he shall take a little of the liver with it, for in another place it distinctly states, (Leviticus 9:10) “and the יותרת מן הכבד [he caused to ascend in fumes]” (Sifra, Vayikra Dibbura d'Nedavah, Section 14 8). על הכבד על הכליות — means, besides the part of the liver and besides the kidneys shall he remove this (the יותרת‎).

וְאֵת֙ שְׁתֵּ֣י הַכְּלָיֹ֔ת וְאֶת־הַחֵ֙לֶב֙ אֲשֶׁ֣ר עֲלֵהֶ֔ן אֲשֶׁ֖ר עַל־הַכְּסָלִ֑ים וְאֶת־הַיֹּתֶ֙רֶת֙ עַל־הַכָּבֵ֔ד עַל־הַכְּלָי֖וֹת יְסִירֶֽנָּה׃

and the two kidneys, and the fat that is on them, which is by the flanks, and the appendage of the liver, with the kidneys, it shall he take away.