The labelling in the dialogue is in plain English. Bind means attach, socket means connection (same as the plug and socket in an electrical cord) IP address is the 'address' of your machine.
The function is useful when your machine has two or more network cards and you want mIRC to use a specific one rather than choosing it's own.
From the help file: The bind sockets to IP option makes mIRC bind all sockets to a specific local IP address, in case you want it to use a different outgoing network connection.
I can't see how it can be 'illustrated' any clearer than that. No offence to people out of the know but I do feel that if someone needs this clarified then they should make themselves aware of simple networking protocols such as TCP/IP, and the like, before trying to configure software to use a specific path.
