What is "tetrahydrocannabinol"

marijuana \marijuana\ n.

1. A strong-smelling Asian plant ( Cannabis sativa), also called hemp, from which a number of euphorogenic and halucinogenic drugs are prepared. The euphoric effect is predominently due to tetrahydrocannabinol ( THC). [Also spelled marihuana.]

   Syn: cannabis, ganja, pot, grass, marihuana, Cannabis sativa.

2. The dried leaves or the female flowers of the hemp plant, which is smoked or chewed to obtain a euphoric effect. The flowers usually have a higher concentration of the active ingredient, tetrahydrocannabinol.

   Syn: cannabis, ganja, pot, grass, marihuana, dope, weed, gage, sess, sens, smoke, skunk, Mary Jane.

tetrahydrocannabinol \tet`ra*hy`dro*can*nab"i*nol\ (t[e^]t`r[.a]*h[imac]`dr[-o]*k[a^]n*n[a^]b"[i^]n[add]l), n. (Chem. & Med.) A chemical substance ( C21H20O2) which is produced by the hemp plant (Cannabis sativa), and is the physiologically active agent of dried preparations of that plant, called variously marijuana, hashish, ganja, hemp, etc.; also called THC. It causes the euphoric effect for which the preparations are smoked or chewed. It is used in medicine in a purified form as an antiemetic (an antinausea agent), especially in conjunction with chemotherapy of cancer. It occurs primarily as the [Delta]1-3,4-trans isomer, also called [Delta]9-THC, with small amounts of the [Delta]6-3,4-trans isomer detectable at about 1%. It is a controlled substance, classified as a hallucinogen, and its possession and distribution is illegal in almost all states of the United States.
--MI11

Cannabis \Can"na*bis\, prop. n. [L., hemp. See Canvas.]

1. (Bot.) A genus of a single species belonging to the order Uricace[ae]; hemp.

2. The Indian hemp plant plant Cannabis sativa syn. Cannabis Indica. See Cannabis Indica, below.

   Cannabis Indica, the Indian hemp, now considered a variety of the common hemp ( Cannabis sativa), originating in Asia but now grown widely around the world. It can be formed into a tough fiber that is used to make rope and tough fabric. The dried leaves and female flowers are smoked or chewed by people to produce a euphoric or hallucinogenic effect, caused mainly by the substance tetrahydrocannabinol (THC) contained in it. The THC-containing products of Cannabis are classified as a controlled substance, and posession and sale are illegal in most states of the United States. Once classified as a narcotic, the plant is now more commonly referred to in the category of euphoric or hallucinogenic agents.

n. (context organic compound English) The psychoactive substance present in cannabis, a hydrogenated derivative of cannabinol.

n. psychoactive substance present in marijuana [syn: THC]

Tetrahydrocannabinol (THC, dronabinol by INN), or more precisely its main isomer (−)-trans-Δ-tetrahydrocannabinol, is the principal psychoactive constituent (or cannabinoid) of cannabis. It can be an amber or gold colored glassy solid when cold, which becomes viscous and sticky if warmed.

Like most pharmacologically-active secondary metabolites of plants, THC in Cannabis is assumed to be involved in self-defense, perhaps against herbivores. THC also possesses high UV-B (280–315 nm) absorption properties, which, it has been speculated, could protect the plant from harmful UV radiation exposure.

THC, along with its double bond isomers and their stereoisomers, is one of only three cannabinoids scheduled by the UN Convention on Psychotropic Substances (the other two are dimethylheptylpyran and parahexyl). It was listed under Schedule I in 1971, but reclassified to Schedule II in 1991 following a recommendation from the WHO. Based on subsequent studies, the WHO has recommended the reclassification to the less-stringent Schedule III. Cannabis as a plant is scheduled by the Single Convention on Narcotic Drugs (Schedule I and IV).

A pharmaceutical formulation is available by prescription in the U.S. and Canada under the brand name Marinol and Cesamet.