look up any word, like bukkake:
 
121.
420
idiots, there are 4 oxygen molecules and 20 carbon molecules in THC, no one in californa invented 420 you social tools!
420,4 oxygen 20 carbon 40 hydrogen
by steven martens March 09, 2006
 
1.
420
So far the majority of you are incorrect.
420's origin IS known.
the term 420 originated at San Rafael High School, in 1971, among a group of about a dozen pot-smoking wiseacres who called themselves the Waldos, who are now pushing 50. The term was shorthand for the time of day the group would meet, at the campus statue of Louis Pasteur, to smoke pot. Intent on developing their own discreet language, they made 420 code for a time to get high, and its use spread among members of an entire generation.
So there ya go, someone's parents out there invented the term 4/20.
And remember this:
There are NOT 420 chemicals in Weed. It's about 315, the num. goes up or down depending on what you're smoking.
4/20 is NOT police code or Maryjane.
And that whole shit about Holland and 4/20 over there being "tea time" for smokers isn't true either.

I know my shit.
by Brandy. April 18, 2003
 
2.
420
Common misconceptions point to crazy theories about weed but the truth is it is actuly a number between 419 and 421.
Guy 1: I counted to 420 today!
Guy 2: Sooo you want to get stoned?
Guy 1: What? What the fuck does that have to do with anything?
by Toxic Ninja October 27, 2006
 
3.
420
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.
by Darius Sunofovich December 31, 2004
 
4.
420
420, indeed, was thought of years ago as the time of day some people got together to smoke pot. Now it is used as code for "Let's go get high." Also, some people consider it to be April 20th that is "National Pot Smoking Day."
I prefer all of the above.
Dude, 420, let's go.
by Lonnie September 29, 2004
 
5.
Supposedly "420" was a code used by the San Rafael police department, however, the department has always denied this. A group known as the "Waldos" claim to have originated 420 in San Rafael in 1971. The group met every day at 4:20 PM after school and eventually began to use 420 as a code for marijuana so they could talk about pot in front of parents and teachers.
Can't wait til 420, I'm going to blaze out of my mind.
by Drew April 04, 2004
 
6.
420
The term 420 is used widely in Cannabis culture as a time to get high, a national day to get high, and cannabis itself.

There are a lot of different theories about how the word was first invented:

:: San Rafael theroy ::
In the early 1970's, a group of teenagers who attended San Rafael High School in San Rafael, California used to get high every day at 4:20 in the afternoon under the Louis Pasteur statue.

:: Bob Dylan theroy ::
In Bob Dylan's song, 'Rainy Day Women #12 && 35,' the lyrics contain 'everybody must get stoned.' 420 comes from the title, as 12 * 35 = 420.

:: Highway 420 ::
In Ontario, Canada in the 60's, marijuana grew freely on one of the Highways. This highway was later renamed in 1972 as Highway 420.

:: The Date 4/20 ::
April 20th is coincidentally (or not..) the birthday of Adolf Hitler who was born on April 20, 1889. It is also interesting to note that the Columbine High School shootings also occured on this date in 1999.

There are many other theories that have been debunked such as the Bob Marley theroy and the Police Code theroy.
You]: "Yo, dude.. it's April 20th - let's go smoke over there!"
Me]: "You also realize that today is Hitler's birthday? Let's go throw some rocks at passing Volkswagen's while smoking mary jane! After all.. hitler invented the VW Beetle"
You]: "GOOD IDEA! This is gonna be the best 420 ever!!"
by daavid May 08, 2006
 
7.
Best holiday(which is today, april 20th)!
4-20! National Smoke Out Day
by Orlando April 20, 2005