What is mean by Hacking

In the cyber security world, the person who is able to discover a weakness in the system  and manages to exploit it to accomplish his goal(Good or Bad) is referred as a Hacker, and the process is referred to as Hacking.
Nowdays, People think that hacking is only hijacking Facebook accounts or defacing websites. Yes it is also part of hacking field but it doesn't mean that it is all there is. This is not even the tip of the hacking.
Hacking is the practice of modifying the features of a system or finding a loophole, i n order to accomplish a goal outside of the creator's original purpose.
Due to the mass attention given to the so called Blackhats or Crackers from the media the reputation of all hackers, even the good ones is damaged.