c.1200, bagge, from Old Norse baggi or a similar Scandinavian source; not found in other Germanic languages, perhaps ultimately of Celtic origin. Disparaging slang for "woman" dates from 1924 (though various specialized senses of this are much older). Meaning "person's area of interest or expertise" is 1964, from Black English slang, from jazz sense of "category," probably via notion of putting something in a bag.
To be left holding the bag (and presumably nothing else), "cheated, swindled" is attested by 1793. Many figurative senses are from the notion of the game bag (late 15c.) into which the product of the hunt was placed; e.g. the verb meaning "to kill game" (1814) and its colloquial extension to "catch, seize, steal" (1818). To let the cat out of the bag "reveal the secret" is from 1760.
bag (bāg)
n.
An anatomical sac or pouch, such as the udder of a cow.
A container of flexible material, such as paper, plastic, or leather, that is used for carrying or storing items.
brown-bag, dime bag, ditty bag, doggy bag, douche bag, fag bag, fleabag, grab-bag, hair bag, half in the bag, have a bag on, in the bag, jiffy bag, let the cat out of the bag, nickel bag, old bag, rum bag, sandbag, sleazebag, slimebag, stash bag, tie a bag on, windbag
(1.) A pocket of a cone-like shape in which Naaman bound two pieces of silver for Gehazi (2 Kings 5:23). The same Hebrew word occurs elsewhere only in Isa. 3:22, where it is rendered "crisping-pins," but denotes the reticules (or as R.V., "satchels") carried by Hebrew women. (2.) Another word (kees) so rendered means a bag for carrying weights (Deut. 25:13; Prov. 16:11; Micah 6:11). It also denotes a purse (Prov. 1:14) and a cup (23:31). (3.) Another word rendered "bag" in 1 Sam. 17:40 is rendered "sack" in Gen. 42:25; and in 1 Sam. 9:7; 21:5 "vessel," or wallet for carrying food. (4.) The word rendered in the Authorized Version "bags," in which the priests bound up the money contributed for the restoration of the temple (2 Kings 12:10), is also rendered "bundle" (Gen. 42:35; 1 Sam. 25:29). It denotes bags used by travellers for carrying money during a journey (Prov. 7:20; Hag. 1:6). (5.) The "bag" of Judas was a small box (John 12:6; 13:29).