marijuana vs Mary Jane

marijuana and Mary Jane both are nouns.

Word	Noun	Adjective	Verb	Adverb
marijuana	Yes	No	No	No
Mary Jane	Yes	No	No	No

As nouns, Mary Jane is a hyponym of marijuana; that is, Mary Jane is a word with a more specific, narrower meaning than marijuana:

marijuana: 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
Mary Jane: street names for marijuana

Other hyponyms of marijuana include Acapulco gold, Mexican green, dope, gage, grass, green goddess, locoweed, pot, sens, sess, skunk, smoke, weed, kief.

marijuana (noun)	Mary Jane (noun)
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	street names for marijuana
a strong-smelling plant whose dried leaves can be smoked for a pleasant effect or pain reduction