An Etymological Dictionary of Astronomy and Astrophysics

1. A branching or division into two parts; a splitting apart.
   

2. A sudden qualitative change in the behavior of a → dynamical system.
   The equation describing the evolution of the system finds several solutions for certain values of a parameter. Systems undergoing a bifurcation do not necessarily return to their original state, even if the parameter returns to its nominal value. See also → chaos.

See also: Verbal noun of → bifurcate.