Marihuana, in its original spelling, is a Spanish slang term that came across the border from Mexico. Many believe Spanish speakers adopted the word from another language, but some suggest that marihuana is actually a euphonic combination of the names María and Juana. If true, the first half of the term could be a nod to Mother Mary, which would certainly make the etymology of marihuana that much more interesting. Either way, the euphonic name combination was certainly not unprecedented. Consider the 14th-century noblewoman María Juana de Padilla or the Catholic saint Mother Juana María Condesa Lluch. Other examples include Duchess Marie Jeanne and Archduchess Maria Johanna Gabriela, both names that translate as María Juana in Spanish. Northeast Argentina even has a town called María Juana! In any case, María and Juana, which translate as Mary Jane in English, were possibly combined to create the word “marihuana” in Spanish.
Cannabis history expert Dr. Barney Warf, the author of High Points and a professor at the University of Kansas, believes this is the most likely origin theory. He told PRØHBTD the following: "I have come across the many different hypotheses that the word itself comes from various possible languages. I have never seen a convincing account of any of those. I think that it's just simply a version of the Spanish María and Juana, which is a very common name in much of Latin America. Frequently, women have two first names. It was probably a slang term that was being used somewhere in Latin America and then got popularized. I tend to use the word cannabis rather than marijuana because marijuana is just one of a number of nicknames for it. Weed, ganja and others. I'm very skeptical of theories that the word marijuana came from any other language besides Spanish."