OpenSource

Open source ComputerSoftware is nominally owned by one entity, such as the FreeSoftwareFoundation, and then licensed out according to an OpenSourceLicense; the license gives the user free use of the software as well access to the SourceCode, so that the software can then be further developed by whoever is interested.  (This needs to be expanded.)

The OpenSourceMovement is a large movement of programmers and other computer users to give easy access to ComputerSoftware.

Among the relevant topics:

DonaldEKnuth, RichardStallman

The GNUProjecT, FreeSoftwareFoundation, DebianLinux distribution, FreeBSD

OpenSourceSoftware: EmacS, TeX, ViM, ApachE, XFrEE, GimP, PhP...