To understand 420 meaning origins, we need to go back to the early 1970s, when a group of high school students in San Rafael, California, known as the Waldos, would meet at 4:20 p.m. to smoke cannabis. They used the code word "420" to communicate their plans without alerting others. The term spread among cannabis enthusiasts and became associated with April 20, a date that many people celebrate by consuming cannabis products.