"Nice idea, but that's not true. The word marijuana derives from the Mexican Spanish: marihuana, and beyond that is of uncertain origin. marijuana (n.) 1918, altered by influence of Spanish proper name Maria Juana "Mary Jane" from mariguan (1894), from Mexican Spanish marihuana, of uncertain origin. manna (n.) Old English borrowing from Late Latin manna, from Greek manna, from Hebrew man, probably literally "substance exuded by the tamarisk tree," but used in Greek and Latin specifically with reference to the substance miraculously supplied to the Children of Israel during their wandering in the Wilderness (Ex. xvi:15). Meaning "spiritual nourishment" is attested from late 14c. Generalized sense of "something provided unexpectedly" is from 1590s." - Marlin Forbes