"Weed, or marijuana refers to preparations of the Cannabis plant intended for use as a psychoactive drug or for medical purposes. 
The herbal form of cannabis consists of the flowers, leaves and stalks of mature pistillate of female plants. The resinous form of the drug is known as hashish.
The major psychoactive chemical compound in cannabis is Δ9-tetrahydrocannabinol. Cannabis contains lots of different chemical compounds, including other cannabinoids like cannabidiol,  cannabinol and tetrahydrocannabivarin, which can result in different effects from those of THC alone..." (*)
Ah, fuck your doc-speak shit," Mike growled and held out his hand, "pass the spliff already!"


(*) thanks for the info, Wikipedia!