marijuana drug use: Police presence at the concert discouraged 420.
The guys at the party were all 420-friendly.
3.
the twentieth day of the fourth month, or the time 4:20, when referenced as a day or time for cannabis consumption or the celebration of marijuana culture:
The head shop has a big pipe sale every year on 420.
Origin of 420
1970-1975
First recorded in 1970-75; a code word derived from the meeting time of a particular group of marijuana smokers in 1971, later popularized by fans of the band the Grateful Dead
