A media access control address (MAC address) of a computer is a unique identifier assigned to network interfaces for communications at the data link layer of a network segment.
Whenever you click on any link in a web browser, the website you are looking at knows to send the link content to your computer and not your neighbours, because your computer sends its IP address sort of like a return address on the envelope.
But as it turns out IP addresses only get you as far as the modem you have in your house and these days most of us have tons of things connected to our routers especially wirelessly phones, laptops, televisions and many other devices, each device on your network has something called a MAC address.
MAC stands for media access control. it identifies which device is which on your local network, so here’s how they work when data arrives at your home from the worldwide internet, your router needs to decide which device to send that data to it, and it does this by keeping track of the MAC addresses of all the devices connected to it, then assigning what’s called a private IP address, usually starting with 192.168 to every device.
Briefly, a MAC address is the unique identifier that is assigned by the manufacturer to a piece of network hardware (such as a wireless card or an ethernet card) and each identifier is meant to be unique to a particular device.