The whole rump - The whole fat tail: i. e., the tail of the kind of sheep well known in the East, and often weighing 15 lbs. and even as much as 50 lbs., when the sheep has been increased by artificial fattening.
Related Commentaries of Leviticus 3:9
Leviticus 3:9
9 And he shall offer of the sacrifice of the peace offering an offering made by fire unto the LORD; the fat thereof, and the whole rump, it shall he take off hard by the backbone; and the fat that covereth the inwards, and all the fat that is upon the inwards,