NOUN (3)

1. a bifurcating branch (one or both of them);

2. the place where something divides into two branches;

3. the act of splitting into two branches;

The Collaborative International Dictionary of English v.0.48:

Bifurcation \Bi`fur*ca"tion\, n. [Cf. F. bifurcation.]
   A forking, or division into two branches.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bifurcation
    n 1: a bifurcating branch (one or both of them)
    2: the place where something divides into two branches
    3: the act of splitting into two branches

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "bifurcation":
   Janus, L, ambiguity, ambivalence, angle, apex, arborescence,
   arborization, bend, bifidity, biforking, biformity, bight,
   bipartition, bisection, branching, branching off, by two, cant,
   chevron, coin, conjugation, corner, crank, crook, crotchet,
   cutting in two, deflection, dichotomy, dimidiation, divarication,
   division, dogleg, doubleness, doublethink, doubling, dualism,
   duality, duplexity, duplication, duplicity, elbow, ell,
   equivocality, fork, forking, furcation, halving, hook, in half,
   inflection, irony, knee, nook, pairing, point, polarity, quoin,
   ramification, subdivision, swerve, treelikeness, trifurcation,
   twinning, two-facedness, twoness, veer, vertex, zag, zig, zigzag