The term Open Source was coined by Bruce Perens, for the debian project, where the users get the complete code of the software, and they get to modify it, use it and redistribute it.

In genera, an open source license is expected to meet the folowing 10 conditions.

1. Free Redistribution: the software can be freely given away or sold. (This was intended to encourage sharing and use of the software on a legal basis.)
2. Source Code: the source code must either be included or freely obtainable. (Without source code, making changes or modifications can be impossible.)
3. Derived Works: redistribution of modifications must be allowed. (To allow legal sharing and to permit new features or repairs.)
4. Integrity of The Author’s Source Code: licenses may require that modifications are redistributed only as patches.
5. No Discrimination Against Persons or Groups: no one can be locked out.
6. No Discrimination Against Fields of Endeavor: commercial users cannot be excluded.
7. Distribution of License: The rights attached to the program must apply to all to whom the program is redistributed without the need for execution of an additional license by those parties.
8. License Must Not Be Specific to a Product: the program cannot be licensed only as part of a larger distribution.
9. License Must Not Restrict Other Software: the license cannot insist that any other software it is distributed with must also be open source.
10. License Must Be Technology-Neutral: no click-wrap licenses or other medium-specific ways of accepting the license must be required.

While the term applied originally only to the source code of software,[4] it is now being applied to many other areas such as open source ecology, a movement to decentralize technologies so that any human can use them. However, it is often misapplied to other areas which have different and competing principles, which overlap only partially.

Opponents of the spread of the label “open source,” including Richard Stallman, argue that the requirements and restrictions ensure the continuation of the effort, and resist attempts to redefine the labels. He argues also that most supporters of open source are actually supporters of much more equitable agreements and support re-integration of derived works and that most contributors do not intend to release their work to others who can extend it, hide the extensions, patent those very extensions, and demand royalties or restrict the use of all other users—all while not violating the open source principles with respect to the initial code they acquired.