30% of respondents to the Civilized Cannabis Culture Poll indicated "pot" was their choice slang word for cannabis, second only to "weed". So how did kitchenware become a byword for marijuana?
The simple answer is it didn't: there's no connection between the pot used for cooking and the pot for baking.
According to the Oxford English Dictionary, the most prominent etymological (word-origin) theory is that "pot" comes from the Mexican term "potaguaya," which may be a word for cannabis leaves, or it could be an acronym for "potación de guayaya," meaning "drink of grief"—a beverage prepared by steeping cannabis buds in wine or brandy.
Did Mexicans consume potaguaya to cope with grief, or did drinking it make them sad? We may never know because the potaciónmight not be real. The OED says there's no evidence to support "potiguyaya" or "potación de guava" as actual terms in Mexican Spanish.
"Potiguaya" does appear in English glossaries of drug terminology slightly earlier than "pot," but the relationship between the two words might be coincidental rather than derivative.
We don't know where "pot" comes from, but we do know when it first appeared in print. African-American writer Chester Himes used the term in his short story "The Way We Live Now" (1938), in which he writes, "She made him smoke pot and when he got jagged [high]…she put him on the street."