Open Source > What is it?
What is Open Source Software?
Most software that you buy is distributed in the form of binary files. This means that the source code has already been converted into a set of instructions that your computer will understand. If you try to look at the contents of these files you'll see that it's impossible for a human to understand.
With Open Source Software, the software is distributed in a different format. You get the source code to the program. You then translate this source code into the computer instructions yourself.
The concept of Open Source Software is also very tightly tied in with the Free Software Movement. This means that Open Source Software is free (as in "free speech") so that you are allowed to change it in any way to want. It is also often free in the other sense (as in "free beer") so that typically it's much cheaper than "closed source" software.