ringtone

n. sound made by a telephone when it rings (term which is used mostly to refer to the customisable sounds available on cellular phones)

A ringtone or ring tone is the sound made by a telephone to indicate an incoming call. The term, however, is most often used to refer to the customizable sounds available on mobile phones. This facility was originally provided so that people would be able to determine when their phone was ringing when in the company of other mobile phone owners.
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