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; 147:47). The fat of sacrifices was
to be burned (Lev. 3:9-11; 4:8; 7:3; 8:25; Num. 18:17. Compare 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).