The word band has several meanings:

1. A group of musicians who play together. A rock band might include guitarists, a drummer, and a singer. School bands play instruments like trumpets, clarinets, and trombones. Jazz bands, marching bands, and garage bands all make music together, though they sound very different from each other.
2. A strip of material that wraps around something. A rubber band stretches to hold papers together. A headband keeps hair out of your eyes. A watchband attaches a watch to your wrist. These bands encircle or bind things together.
3. A range or group of related things. Scientists might study a band of radio frequencies. A tax band groups people who pay similar rates. In this sense, a band marks boundaries, like saying “temperatures in the 70-80 degree band.”

The musical meaning is most common today, but all these definitions share an idea of things joined or grouped together. When musicians form a band, they're binding their talents together, just as surely as a rubber band binds a stack of cards.