The Collaborative International Dictionary of English v.0.48:

Fork \Fork\, v. i. [imp. & p. p. Forked; p. pr. & vb. n.
   Forking.]
   1. To shoot into blades, as corn.
      [1913 Webster]

            The corn beginneth to fork.           --Mortimer.
      [1913 Webster]

   2. To divide into two or more branches; as, a road, a tree,
      or a stream forks.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Forked \Forked\, a.
   1. Formed into a forklike shape; having a fork; dividing into
      two or more prongs or branches; furcated; bifurcated;
      zigzag; as, the forked lighting.
      [1913 Webster]

            A serpent seen, with forked tongue.   --Shak.
      [1913 Webster]

   2. Having a double meaning; ambiguous; equivocal.
      [1913 Webster]

   Cross forked (Her.), a cross, the ends of whose arms are
      divided into two sharp points; -- called also cross
      double fitch['e]. A cross forked of three points is a
      cross, each of whose arms terminates in three sharp
      points.

   Forked counsel, advice pointing more than one way;
      ambiguous advice. [Obs.] --B. Jonson. -- Fork"ed*ly,
      adv. -- Fork"ed*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

forked
    adj 1: resembling a fork; divided or separated into two
           branches; "the biramous appendages of an arthropod";
           "long branched hairs on its legson which pollen
           collects"; "a forked river"; "a forked tail"; "forked
           lightning"; "horseradish grown in poor soil may develop
           prongy roots" [syn: bifurcate, biramous, branched,
           forked, fork-like, forficate, pronged, prongy]
    2: having two meanings with intent to deceive; "a sly double
       meaning"; "spoke with forked tongue" [syn: double,
       forked]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "forked":
   V-shaped, Y-shaped, akimbo, angular, arboreal, arborescent,
   arboriform, bent, biforked, bifurcate, bifurcated, bisected,
   branched, branching, branchlike, cleft, cloven, cornered, crooked,
   crotched, dendriform, dendritic, dichotomous, dimidiate, divided,
   forking, forklike, furcal, furcate, geniculate, geniculated,
   halved, hooked, jagged, knee-shaped, pointed, pronged, ramified,
   ramous, riven, saw-toothed, sawtooth, serrate, sharp,
   sharp-cornered, split, tree-shaped, treelike, tridentlike,
   trifurcate, trifurcated, zigzag



The Jargon File (version 4.4.7, 29 Dec 2003):

forked
 adj.,vi.

    1. [common after 1997, esp. in the Linux community] An open-source software
    project is said to have forked or be forked when the project group fissions
    into two or more parts pursuing separate lines of development (or, less
    commonly, when a third party unconnected to the project group begins its
    own line of development). Forking is considered a Bad Thing ? not merely
    because it implies a lot of wasted effort in the future, but because forks
    tend to be accompanied by a great deal of strife and acrimony between the
    successor groups over issues of legitimacy, succession, and design
    direction. There is serious social pressure against forking. As a result,
    major forks (such as the Gnu-Emacs/XEmacs split, the fissionings of the
    386BSD group into three daughter projects, and the short-lived GCC/EGCS
    split) are rare enough that they are remembered individually in hacker
    folklore.

    2. [Unix; uncommon; prob.: influenced by a mainstream expletive] Terminally
    slow, or dead. Originated when one system was slowed to a snail's pace by
    an inadvertent fork bomb.


The Free On-line Dictionary of Computing (30 December 2018):

forked

    (Unix; probably after "fucked") Terminally slow, or
   dead.  Originated when one system was slowed to a snail's pace
   by an inadvertent fork bomb.

   [Jargon File]

   (1994-12-14)