420 (cannabis culture)

420, 4:20, or 4/20 (pronounced four-twenty) is a code word used by people who smoke cannabis to talk about the drug. It is especially used to talk about smoking cannabis at 4:20pm (16:20) in the afternoon, and for the day April 20 (4/20 in the American calendar).
The term appeared in 1971 from five American high school students in California.
April 20 became the day of cannabis-related events, celebrations, and protests.