Thou
A "Thou" is a gram a marijuana, stemming from the words "a thousand." A Thousand can be said as a "G". In the drug culture a "G" is a gram.
"Hey Dude, wanna hang out later?"
"Oh yea for sure dude, i think i'm gonna pick up a thou or two real quick and after that wanna hit Medusa, she'll get us stoned!"