ringback

回铃声（电话服务）；有回铃音的电话

释义与例句

n.
  1. 1.

    The sound transmitted back to a caller to indicate that the telephone they are calling is ringing.

    不可数 媒体 工程
  2. 2.

    A telephone feature allowing a person to receive an automatic call back when a busy line becomes free.

    不可数 媒体 工程

词源

Deverbal from ring back.

来源：wiktionary