Yeah.. but don't get all scared Nsuch.
A hack is simply using something for something what it was not originally intended for.
Lemme give an example: A screw is meant to be screwed using the tool "screwdriver" but if you hit it hard enough with a hammer, you can still hang your painting without the aid of a screwdriver.
And presto, your first hack!
Now computer hackers generally create little programs to use things what they are not initially intended for. Sometimes these little programs, or tools can't even be called real programs because they are only meant for a single task, don't have a real user interface, or don't work all the time. These are called tools too.
Ofcourse these tools can be used to do illegal stuff just like the hammer can easily be used to break into houses and cars. That doesn't mean the hammer or the one using it is a criminal.
So there you go. I'm a Hacker, but it can't be determined if I am doing anything illegal (unless ofcourse I'm careless) Muhahahaa!!!!
A hack is nothing more then the crude application of science in order to perform a specific task.