Four-twenty, 420, 4:20, or 4/20 is slang for marijuana and in cannabis culture for the consumption of cannabis. This slang term has come to represent the “ideal” time for smoking marijuana, being 4:20 pm, and has become synonymous with the date 4/20 being designated as “national pot day.”
It’s a commonly known term in cannabis culture, but most people don’t know where it originated from. The prevailing theory is that, in 1971, the terms was invented by five high school students – Mark Gravich, Jeffrey Noel, Larry Schwartz, Dave Reddix, and Steve Capper, who lived in San Rafael, California at the time.
They called themselves the Waldos, a play on words stemming from them sitting on a wall outside their school to survey the nearby area for a hidden cannabis crop based on a treasure map made by the grower. Having agreed to meet every day at 4:20, the plan became code-named “4:20,” apparently giving rise to the term as slang for consuming cannabis.