| BDFL |
Benevolent Dictator For Life — a project lead with final say |
| CLA |
Contributor License Agreement |
| Copyleft |
License condition requiring derivatives to keep the same freedoms |
| DCO |
Developer Certificate of Origin; certified via Signed-off-by: |
| FOSS / FLOSS |
Free (Libre) and Open Source Software |
| Fork |
A copy of a project that develops independently |
| Open core |
Open source core with proprietary add-ons |
| OSI |
Open Source Initiative; maintains the Open Source Definition and approves licenses |
| FSF |
Free Software Foundation; maintains the GPL family |
| Permissive |
License with minimal conditions (MIT, BSD, Apache) |
| SBOM |
Software Bill of Materials — a list of everything in a build |
| Source-available |
Source is visible but the license isn't open source (BSL, SSPL) |
| SPDX |
Standard identifiers for licenses (MIT, Apache-2.0, GPL-3.0-or-later) |
| Tivoization |
Using hardware restrictions to block modified versions of free software |
| Upstream / downstream |
The original project vs. those who consume or repackage it |