Easton's Bible Dictionary: M. G. Easton, M.A., D.D.

Fat

(Heb.heleb) denotes the richest part of the animal, or the fattest of the flock, in the account of Abel's sacrifice (Gen. 4:4). It sometimes denotes the best of any production (Gen. 45:18; Num. 18:12; Ps. 81:16, 147:14). The fat of sacrifices was to be burned (Lev. 3:9-11, 4:8, 7:3, 8:25; Num. 18:17. Comp. Ex. 29:13-22; Lev. 3:3-5).

It is used figuratively for a dull, stupid state of mind (Ps 17:10).

In Joel 2:24 the word is equivalent to "vat," a vessel. The hebrew word here thus rendered is elsewhere rendered "wine-fat" and "press-fat" (Hag. 2:16; Isa. 63:2).