The nationally accepted time or date on which the majority of occasional or chronic marijuana users choose to get high from the smoke of cannabis leaves.
Although it is apparent that 4:20 may indeed have originated from H.P. Lovecraft, in addition to many other contrasting theories, it has nevertheless been apparent to me that the first two digits of the number are 42, a number which clearly derives its significance from Douglas Addams in The Hitchhiker's Guide to the Galaxy, in which he claims the number to be "the answer to Life, the Universe, and Everything."
Nevertheless, the true meaning of 4:20 differs from person, and perhaps it is best that everyone may have his or her own personal meaning of the national holiday.
Person 1: "You know, I really wonder...Why is it that we all choose 4/20 at 4:20 to get high?"
Person 2: "You know, I'm really too stoned to care right now."
Person 1: "Yeah. Now what were we just talking about?"