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123.
A band that got together in 1988 in California. They were first known as Sweet Children. Their name Green Day was used as a codename for when they were going o smoke marijuwana hence GREEN DAY (second definiton)In 1994, they became famous for their album Dookie and pretty famous for their epic mud war at a live concert. They progressed to a few different styles as shown in Good Riddance(Time of Your Life) and their more recent album 21st Century Breakdown. Even though their style has changed, Billie Joe Armstrong explains this as a way to connect to more fans and a way to experiment with different genres that he is interested in. They became more widely known for their album, American Idiot, which was a turning piont for their career as the band put it, after their masters for a different idea were stolen. After fooling around and realizing that they had more fun and got more emotion out of the new ideas, they changed their style to what they believed was better. Billie Joe Armstrong is also known for the band, Pinhead Gunpowder in 1993 (I believe) and Dirnt, Cool and Armstrong composed another band, Foxburrow Hottubs that came out in 2007, which wasn't quite that succesful. Also, The Network. All of the members are bisexual and have no regrets what so ever.
Green Day is one of my favorite bands even though they have mixed it up over the years
by HeroMustDrown March 26, 2011
 
1.
A day spent smoking marijuana.
Saturday was a green day.
by Anonymous September 18, 2003
 
2.
A sort-of punk rock band that was good but not extremely popular until recently, when thousands of teenyboppers found out about them on TRL, believing their newest and worst CD to date to be "teh bset". Now every fourteen year old in the country rants about how great Boulevard of Broken Dreams is and are known to exclaim things such as "OMG BILLY JOE IS HAWT!!!1" and "DONT WANNA BE AN AMERICAN IDIOT!!12". Their new CD is mediocre at best, so please listen to their other albums instead.
The typical Green Day "fan" has never heard of Nimrod or Kerplunk, but totally eats up the new pop-punk garbage.
by Chernorizets Hrabr March 16, 2005
 
3.
1. A day which is mainly spent smoking the drug marijuana, in an effort to end boredom. May have originated in California in the mid-80's.

2. A popular punk rock band with members from Rodeo and Willits, California.
1. I had a green day yesterday.

2. Mike Dirnt and Tre Cool are also members of Green Day.
by Crispy September 01, 2004
 
4.
Quality band which poeple tend to see as sell outs because of their last album American idiot. For me they will always be remembered for Insmoniac and dookie two of the best punkish albums I have in my collection. Unfortunatly their main following now consists of teeny boppers who only discovered Green day existed when Boulevard of broken dreams came out and wouldn't know "At the library" from "Westbound sign" Still i suppose they had to find someone to fantasise over after Busted split up. DAMN YOU CHARLIE!!
girl 1: "wow have you heard that new band Green day?"
girl 2: "Yeah, billie joe is gorgeous"
me: "For gods sake! they have been around for 15 odd years!"
girl 3: "really? wow do you reckon Nirvana will ever get back together? that would be qualtiy"
me: *sound of me crying on the floor in utter despair*
by Guvnor P June 27, 2005
 
5.
1) A day to smoke weed.

2) Popular American pop-punk band with such classics as Good Riddance (Time of Your Life), Basket Case and Longview. Sometimes said to be inspiration for various later pop-punk bands.
1) It was a green day.
2) I am going to the Green Day concert next week.
by jazzpup February 04, 2005
 
6.
1) An awesome rock band lead by singer Billie Joe Armstrong that has many hits like When I Come Around, Welcome to Paradise, Basket Case, She, Brain Stew, Time Of Your Life, Warning, Minority, and Don't Wanna Fall In Love
2) A day when you just sit around and do nothing but smoke weed
1) Man, right now I'm listening to a Green Day CD and the songs are awesome!
2) That stoner's has 1 too many green days. He's trippin, man!
by 000 March 22, 2004
 
7.
A day when one who personally does not have any marijuana of there own, still manages to get high all day, via friends, or just being in the right places at the right times.
"I was out of weed, but thanks to the generosity of my friends, I had a green day."
by Hondro March 03, 2004