A multicast address is a special type of network address used to send data to multiple devices simultaneously. Unlike a unicast address, which targets a single device, a multicast address allows a sender to transmit information to a group of devices that are interested in receiving that data. This is commonly used in applications like video conferencing and streaming media. In the Internet Protocol version 4 (IPv4), multicast addresses range from 224.0.0.0 to 239.255.255.255. Devices that want to receive multicast traffic must join a specific multicast group, identified by its multicast address. This efficient method reduces network congestion by minimizing the number of individual transmissions needed.