A Fixed Point for which the Stability Matrix has equal Negative Eigenvalues.
See also Elliptic Fixed Point (Differential Equations), Fixed Point, Hyperbolic Fixed Point (Differential Equations), Stable Node, Stable Spiral Point, Unstable Improper Node, Unstable Node, Unstable Spiral Point, Unstable Star
References
Tabor, M. ``Classification of Fixed Points.'' §1.4.b in
Chaos and Integrability in Nonlinear Dynamics: An Introduction. New York: Wiley, pp. 22-25,
1989.