The number 420 is a euphemism describing one's support for cannabis and drug culture. The origin of the term is unknown. As with any socially taboo subject, a large amount of urban legend surrounds the origin of this term.
An origin story according to Snopes.com and The Straight Dope claims that in the early 1970s a group of teenagers at San Rafael High School in San Rafael, California used to meet every day to smoke marijuana after school at 4:20 PM. The time became a code word for the drug, and usage spread. 4:20 PM has since become a popular time to "smoke out."
Another possible origin of the term can be found in the works of H.P. Lovecraft. A short story of his, entitled "In the Walls of Eryx" and first published in Weird Tales [34, No. 4 (October 1939), pp50-68], contains this passage:
- I had encountered at least one of those curious mirage-plants about which so many of our men told stories. Anderson had warned me of them, and described their appearance very closely - the shaggy stalk, the spiky leaves, and the mottled blossoms whose gaseous dream-breeding exhalations penetrate every existing make of mask...Although everything was spinning perilously, I tried to start in the right direction and hack my way ahead. My route must have been far from straight, for it seemed hours before I was free of the mirage-plant's pervasive influence. Gradually the dancing lights began to disappear, and the shimmering spectral scenery began to assume the aspect of solidity. When I did get wholly clear I looked at my watch and was astonished to find that the time was only 4:20. Though eternities had seemed to pass, the whole experience could have consumed little more than a half-hour.
Others theories include:
- The number is a police numeric code for a drug bust
- There were, at one time, believed to be 420 chemicals in marijuana.
- April 20th, or 4-20, is the last day on which one is supposed to plant cannabis seeds
- The Beatles song "Come Together" is 4:20 in length
Hardcore smokers smoke-out at 4:20 AM, claiming that 4:20 PM is actually 16:20 (military time). Really, really hardcore smokers smoke-out at both 0420 hours and 1620 hours.
"Hey, it's 420" or "420 dude" are common expressions.