A bandana is a colorful piece of cloth that can be tied around your head or at your neck. Most bandanas are squares folded into a triangle shape before they're tied.
You can also call a bandana a "kerchief," and traditionally it's a solid color with black or white paisley print, although they come in many styles. Some people use bandanas to hold their sweaty hair back, while others like the jaunty style of a bandana around the neck, scarf-like. Bandana is from the Hindi bandhnu, a style of fabric dying, rooted in the Sanskrit badhnati, "binds," from the way cloth is tied before it's dyed.