/ ˈkɔːlbæk; NAmE / noun
1.
[ C ] a telephone call which you make to sb who has just called you
2.
[ U , C ] = ringback
3.
[ U , C ] ( computing ) a process by which the user of a computer or telephone system proves their identity by contacting a computer, which then contacts them
4.
[ C ] ( especially NAmE ) an occasion when you are asked to return somewhere, for example for a second interview when you are trying to get a job
5.
[ C ] an occasion when people are asked to return goods that they have bought, usually because they are not safe