Free as in freedom to do what you want with it, not free as in zero cost.
It is a computer software distributed under terms that allow the software users to run the software for any purpose as well as to study, change, and distribute the software and any adapted versions. Free software is a matter of liberty, not price: users, individually or collectively, are free to do what they want with it, including the freedom to redistribute the software free of charge, or to sell it, or charge for related services such as support or warranty for profit.
Open source means the source code of the software is open to all. Anyone who uses the software can study, change, and distribute the software to anyone else and for any purpose.
It is a computer software with its source code made available with a license in which the copyright holder provides the rights to study, change, and distribute the software to anyone and for any purpose. Open-source software may be developed in a collaborative public manner. According to scientists who studied it, open-source software is a prominent example of open collaboration.
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