multicast
(1) To transmit data to multiple recipients on the network at the same time using one transmission stream to the switches, at which point data are distributed out to the end users on separate lines. Contrast with "unicast," in which there is a separate transmission stream from source to destination for each recipient. When sending large volumes of data, multicast saves considerable bandwidth over unicast. See IP multicast, IGMP and SRM.
(2) In digital television broadcasting, to send multiple standard TV (SDTV) programs in the allotted bandwidth, rather than one high-definition TV (HDTV) program.
