420 (Four Twenty)

Definition: 420 (four-twenty) is slang for cannabis and for consuming it, and April 20 (4/20) is the unofficial cannabis holiday celebrated worldwide. The term traces back to 1971, when a group of San Rafael High School students in Northern California, known as the Waldos, used “4:20” as their code for meeting after school to search for an abandoned cannabis crop and smoke.

Where Did 420 Come From?

According to the Waldos’ own account, reported widely including by the San Francisco Chronicle, the group met at 4:20 p.m. by a statue of Louis Pasteur on campus. The phrase spread through their connections to the Grateful Dead’s circle, and in the early 1990s High Times magazine helped popularize it after a flyer inviting people to smoke “420” on April 20 circulated at Dead shows.

What 420 Doesn’t Mean

Popular myths say 420 is a police code for cannabis, the number of chemicals in marijuana, or connected to a historic date. None of those are true. The high school origin is the best-documented explanation.

How Is 4/20 Celebrated?

4/20 has grown into a mix of celebration, commerce, and activism. People gather for festivals and smoke-outs, dispensaries run some of their biggest sales of the year, and advocates use the day to push for legalization and criminal justice reform. Many people also mark 4:20 every day as a casual toke time.

Is There a Similar Day for Concentrates?

Yes. 710, or July 10, celebrates cannabis oils and concentrates, because “710” flipped upside down spells “OIL.”

Related terms: 710, Green Wednesday, Dispensary, Strains

Sources: San Francisco Chronicle: Heads of the class, the 420 origin story.