fork
In the open-source community, a fork is what occurs when two
(or more) versions of a software package's source code are being
developed in parallel which once shared a common code base, and
these multiple versions of the source code have irreconcilable
differences between them. This should not be confused with a
development branch, which may later be folded back into the
original source code base. Nor should it be confused with what
happens when a new distribution of Linux or some other
distribution is created, because that largely assembles pieces
than can and will be used in other distributions without
conflict.
Forking is uncommon; in fact, it is so uncommon that individual instances loom
large in hacker folklore. Notable in this class were the GCC/EGCS fork (later
healed by a merger) and the forks among the FreeBSD, NetBSD, and OpenBSD
operating systems.