> /v1/glossary/open-source-definition · CONCEPT
The Open Source Definition
The OSI's 10-point definition of what qualifies as open source software.
The Open Source Definition (OSD) is maintained by the Open Source Initiative (OSI) and consists of 10 criteria a license must meet to be called "open source." It was derived from the Debian Free Software Guidelines.
The 10 criteria, in summary: 1. Free redistribution 2. Source code available 3. Derived works permitted 4. Integrity of the author's source code 5. No discrimination against persons or groups 6. No discrimination against fields of endeavor 7. License must be redistributable 8. License must not be specific to a product 9. License must not restrict other software 10. License must be technology-neutral
Source-available licenses like BSL, SSPL, ELv2, and FSL fail the OSD on criteria #5, #6, or #9 — typically because they discriminate against commercial competitors (cloud providers) or restrict combination with other software. The OSI maintains an approved license list, and "open source" without OSI approval is contested terminology.
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