What is “420”?

420 is slang in cannabis culture for the consumption of cannabis, especially smoking cannabis around the time 4:20 p.m. and also refers to cannabis-oriented celebrations that take place annually on April 20 (which is 4/20 in U.S. form)

420 (noun):
  1. Pronounced: /fôrˈtwen(t)ē/
  2. Slang for cannabis, a time to smoke cannabis, the cannabis number.
  3. In 1971, five high school students  in San Rafael, California, calling themselves the Waldos because “their chosen hang-out spot was a wall outside the school”. The Waldos designated the Louis Pasteur statue on the grounds of San Rafael High School as their meeting place, and 4:20 p.m. as their meeting time, which ultimately evolved into a code-word that the teens used to mean consuming cannabis.
  4. Dial-code of the Czech Republic
Usage Examples

“It’s 4;20 somewhere man.”

“Snoop dogs favorite number is 420.”