A multicast group is a method used in computer networking to send data from one source to multiple destinations simultaneously. Instead of sending individual copies of the same data to each recipient, the source sends a single copy to a specific multicast address. Devices that want to receive this data join the multicast group, allowing them to access the information without overwhelming the network. Multicast groups are commonly used in applications like video conferencing, live streaming, and online gaming, where many users need to receive the same data at the same time. This approach is more efficient than unicast (one-to-one) or broadcast (one-to-all) methods, as it reduces network traffic and conserves bandwidth.