From WordNet (r) 3.0 (2006) [wn]:
marihuana
n 1: a strong-smelling plant from whose dried leaves a number of
euphoriant and hallucinogenic drugs are prepared [syn:
marijuana, marihuana, ganja, Cannabis sativa]
2: the most commonly used illicit drug; considered a soft drug,
it consists of the dried leaves of the hemp plant; smoked or
chewed for euphoric effect [syn: cannabis, marijuana,
marihuana, ganja]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
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}.
[WordNet 1.5]
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.
[WordNet 1.5]