What does Open Source actually mean?

you must have heard this term called open source many a times, and interpreted it as just FREE OF COST, but is it so?? does it mean just free of cost? NOPE..

have a look at this article for the answer to your question..

Most software that you buy or download only comes in the compiled ready-to-run version. Compiled means that the actual program code that the developer created, known as the source code, has run through a special program called a compiler that translates the source code into a form that the computer can understand. It is extremely difficult to modify the compiled version of most applications and nearly impossible to see exactly how the developer created different parts of the program. Most commercial software manufacturers see this as an advantage that keeps other companies from copying their code and using it in a competing product. It also gives them control over the quality and features found in a particular product.

Open source software is at the opposite end of the spectrum. The source code is included with the compiled version and modification or customization is actually encouraged. The software developers who support the open source concept believe that by allowing anyone who's interested to modify the source code, the application will be more useful and error-free over the long term.

To be considered as open source software by the software development industry, certain criteria must be met:

• The program must be freely distributed (It can be part of a package that is sold though, such as Red Hat has done with Linux in the example below).
• Source code must be included.
• Anyone must be allowed to modify the source code.
• Modified versions can be redistributed.
• The license must not require the exclusion of other software or interfere with the operation of other software. 

I hope now you will have a clear idea about, what open source actually means?