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4.
20 ounce of weed or dub of weed
got a 20 bag shorty better blaze dat shyt
by chris March 07, 2005
 
1.
not 20 oz, dumbass, thats 1 and 1/4 lbs of marijuana. A 20 bag is $20 worth of weed, depending on area, and tiem of year, the actual weigth will vary
buyer: Can i buy a 20 bag?
by gunjah March 25, 2006
 
2.
rather than just marijuana, a '20bag' denotes a deal of any illicit substance to the value of £20 / $20 and could just as easily contain rock, powder or tablets.
yo, you weighed down? what u got?

all the usuals man, nothin' smaller than a 20 bag though...
by 20bag May 19, 2007
 
3.
2 grams of marijuana, ganja, weed, that green shit
yo send on a 20 bag
u got $20?
ya bro send!
by JoeBro20109 June 13, 2010