To add to the definition regarding "
The Waldos," I'd like to note that in an article of High Times containing an interview with
the waldos, one of them told this story:
We had heard rumors that one of the members brothers had planted a pot patch in the wooded area around town. We all wanted to go look for this patch of weed, so we devised to meet eachother by the statue of
Louis Pasteur after school. Since we all had after school activities or electives that lasted about fifty minutes, and since it took about ten minutes to get from school to our after school activities, and another ten minutes to walk from the activites to the statue. Since there were many of us we decided that 420 would be a good time to meet so we could go search for the patch of pot. We never did find it, but we had lots of fun getting high while trying to look for it.
Therefore, when they were at school, when they saw eachother between classes they would secretively say "420" and maybe give the thumb-and-pointer-finger-to-the-mouth sign to indicate that that was when they would meet to look for the weed patch. Since
the waldos were such legendary potheads, when people who were not
waldos saw this, it caught on and they assumed it was a
secret code word for pot.