A means of installing software form source using a package manager based on Gentoo's portage.
An effort to bring the virtues of Gentoo Linux to users on different operating systems, by means of installing in a "prefix".
Usually, Gentoo's Portage installs in the root of the filesystem hierarchy, '/'. On systems other than Gentoo Linux, this usually results in problems, due to conflicts of software packages, unless the OS is adapted like Gentoo/FreeBSD. Instead, Gentoo Prefix installs with an offset, allowing to install in another location in the filesystem hierarchy, hence avoiding conflicts. Next to this offset, Gentoo Prefix runs unprivileged, meaning no root user or rights are required to use it.
Using an offset, a "prefix", it is possible for many "alternative" user groups to benefit from a large part of the packages in the Gentoo Linux Portage tree. Currently users of the following systems successfully run Gentoo Prefix: Mac OS X on PPC and x86, Linux on x86, x86_64 and ia64, Solaris 10 on Sparc, Sparc/64, x86 and x86_64, FreeBSD on x86, AIX on PPC and Interix on x86