Sure Nirvana were a Grunge band, but they were mainstream. Mainstream Grunge isn't real Grunge in my opinion. The Real Grunge bands were Mudhoney, Alice In Chains, Melvins, Soundgarden, Mother Love Bone, Screaming Trees, Green River, Malfunkshun etc.

Smashing Pumpkins, Jane's Addiction, and Sonic Youth, although great bands, were NOT Grunge.

a type of music that is somewhat dirty and garage like alice cooper but the best grunge band ever was nirvana

A type of music scence originated in Seatle sparked off into the mainstreem by a little band named Nirvana. A cross between Punk, Rock, little of Metal, but mostely early Punk and other shit. Good stuff.

"Grunge is not flannel. Grunge is not long hair. Grunge is not Alice In Chains and whatever. I think Grunge is just a bunch of friends drinking a lot of Henry's and trying to play music when you really can't." --Dave Grohl

A sub-genre of Rock 'N' Roll, which is a cross between two of the sub-genres Punk and Metal.
Rock: Grunge.

The stuff that grows on shower curtains. A term used to exploit alternative bands or basically any band from seattle in the early 90s. Grunge ended more or less when Kurt Cobain died, as well as with everyone commercializing it (specifically what most bands rebel against).
Grunge attire consists of flannel shirts, ripped jeans, Doc Martens/Chuck Converses, as well as ripped babydoll dresses, smeared makeup, and combat boots for girls. True "grungies" dont brush hair.

Stupid term used primarily by journalist in the early 90s, because the thought they needed a new word for rock music.