A special type of networking address that is reserved for sending messages to all machines on a given network segment. Generally, a broadcast address is a MAC destination address of all F's
Just like the postal service, a computer must know where it is sending information. The network address is a set of unique identifying sets of information that can be used to find the right destination. While many may have heard of such an identifier being used to crack identify theft schemes and other sorts of online crime, that is really just a small part of the overall importance of the address. Nearly all information will require this address.