computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose.

Open source intelligence is the collection and analysis of data gathered from open sources (overt sources and publicly available information) to produce actionable intelligence.

Open-source licenses are software licenses that allow content to be used, modified, and shared.

software that is available under a license that grants the right to use, modify, and distribute the software, modified or not, to everyone free of charge.