Open source is software whose recipe is public for anyone to read and improve. An open source project, release it open source, open source tools.
The point is the licence rather than the price: the source code may be read, changed and passed on, and most of the internet runs on it. The term was coined in 1998 as a business-friendly name for what had been called free software.
1phraseopen sourceSoftware whose code is public and may be changed.
“The software is open source, so anyone can read the code and improve it.”
open source is a kind of software.
Also accepted in games: open-source
Coined by Christine Peterson in 1998 as a plainer name for what had been called free software.
open + source, coined by Christine Peterson in 1998 for software as an umbrella term to encompass existing concepts such as free software, freedomware and sourceware.
Etymology from Wiktionary, CC BY-SA
Practised in Technology & Internet, Computing & Code