Headphones are personal audio devices worn over or inside the ears to listen to sound from various sources such as music players, computers, or mobile phones. They consist of speakers (drivers) that convert electrical signals into sound waves directly heard by the listener. Headphones come in different types including over-ear, on-ear, and in-ear styles, offering varying levels of comfort, sound quality, and portability. They typically have a headband or ear hooks to secure them in place and can feature additional functionalities like noise cancellation or wireless connectivity.