MAC address is a network address,assigned to network interface card for unique identification by manufacture.It is 48bit,six octet in length,written in hexadecimal (ex- 00:2a:db:38:9c:f1). The no of data transmission process (ethernet cable, wi-fi, bluetooth)  available in our computer is equals to no of different mac address.
Media Access control address
Mac address is same as IMEI no of mobile,it is just an home address and cannot be change