Sone is a term used to refer to a unit of loudness in acoustics. It measures how loud a sound is perceived by the human ear, with one sone being equivalent to the loudness of a 1 kHz tone at 40 decibels. The sone scale is linear, meaning that a sound that is twice as loud as another is measured as two sones. The concept of sone is important in fields like audio engineering and sound design, where understanding human perception of sound is crucial. It is often used alongside other measurements, such as decibels and phon, to provide a comprehensive understanding of sound levels.