A girl band is a type of cliché J-pop group.
Similar to a boy band, girl bands typically produce cut-and-paste vaguely relatable songs about love, are thought of as puppets of a corporation, and the members look alike, only distinguishable by their fans.
However, unlike boy bands, girl bands sometimes consist of more than 10 (and up to 48) people, instead of the boy band median of 5.
The most famous girl band would be AKB48 (not to be confused with AK-47, which is a kind of gun). True to its name, AKB48 hail from the region of Akihabara and consist of 48 (!) members, who mostly disperse in manageable boy-band-sized groups. There are sister groups called HKT-, JKT-, NMB-, and SKE48.
Another girl band older than AKB48 is Morning Musume. Through the years, the number of members has fluctuated between 5 and 15 members, and as of now (December 2014) there are 10 members and 4 waiting to join. Their biggest hit is called Love Machine.
Girl: "Which member of AKB48 is your favorite?"
Guy 1: "WTF? Everyone in AKB48 looks the same."
Guy 2: "I seriously can't tell two girl bands apart."
Girl: "You guys suck."
by cutesy pastel living doll December 28, 2015
Someone obsessed with female-fronted rock bands, usually male.

Often abbreviated to "GBG," a girl-band geek is someone who prefers bands led by women over bands led by men, often to the point of critically accepting or rejecting bands solely based on the gender of their members, rather than on their talents or productions.
Terry's such a GBG that the only time he listened to Black Flag is when Kira Rosselaer played with them...
by SG Fan October 31, 2004
A girl that has 3 or more numbers in her phone from guys that are in different bands.
OMG I just hung out with the vocalist of Attack Attack! He's staying at my house tonight because they need a place to stay on tour!

Oh Matty Mullins? I know him!

Band Girl
by Vin-Fresh November 12, 2013
Girls who are always putting out in south eastern FLA.
ay man i need some pussy..get those band girls
by gettingipper March 4, 2011
Girls who can blow hard. She has big lungs and a big personality. When she walks by all the guys stare. She's also fabulous with dirty jokes.
See her? She's obviously a band girl.
by Boo1124 February 13, 2021