Meaning

noun any plant of the genus Cannabis; a coarse bushy annual with palmate leaves and clusters of small green flowers; yields tough fibers and narcotic drugs

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

originLearned borrowing from Latin cannabis (“hemp”), borrowed from Ancient Greek κάνναβις (kánnabis). See there for more. Further reading at Etymology of cannabis on Wikipedia. Doublet of canvas and hemp.

Etymology from Wiktionary, CC BY-SA 3.0