Cannabis, also known as marijuana (sometimes spelled "marihuana") among many other names,a[›] refers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug or for medicinal purposes. The English term marijuana comes from the Mexican Spanish word marihuana. According to the United Nations, cannabis "is the most widely used illicit substance in the world."
The typical herbal form of cannabis consists of the flowers and subtending leaves and stalks of mature pistillate of female plants. The resinous form of the drug is known as hashish (or merely as 'hash').
The major psychoactive chemical compound in cannabis is Δ9-tetrahydrocannabinol (commonly abbreviated as THC). Cannabis contains more than 400 different chemical compounds, including at least 66 other cannabinoids (cannabidiol (CBD), cannabinol (CBN) and tetrahydrocannabivarin (THCV), etc.) which can result in different effects from those of THC alone.