WordNet
three-way calling
n. a way of adding a third party to your conversation without the assistance of a telephone operator
Wikipedia
Three-way calling
- redirect conference call
Usage examples of "three-way calling".
Phonetic telephone numbers became feasible in some cities a few years ago when local phone companies began replacing their old electromechanical switching equipment with computer-controlled electronic toys, which simultaneously made possible such modern conveniences as call forwarding and three-way calling.