Using something and change it, and make it do what you want with it.
Commonly used in the opensource communety becose every one can (re)use eatch other source code.
Confusing a computer program to give you access to that machine is also a hack
. Doing this becose you want to test securety is a white hat
Intendedly useing a hack to take over that pc to do your bidding is a cracker
or black hat
Downloading hacks and try them to gain access to a computer with out knowing that it realy does is a script kiddy
putting linux on the nintendo DS is a good example of hacking.
the DS was not intended to do it but they made it do it.