"Hum" refers to a low, continuous sound made by humans or animals, often produced by vocalizing without articulating words. It can be a soothing sound, commonly associated with relaxation or concentration. People often hum when they are happy, lost in thought, or trying to remember a tune. In music, humming is a way to convey melodies without using lyrics. It can be a form of expression in various genres, from classical to pop. Additionally, hummingbirds are named for their humming sound, which is created by their rapidly flapping wings.