• In mathematics, a fixed point of a function f is an argument x such that f(x) = x; see fixed point (mathematics).
• In physics, a fixed point usually describes a quantum field theory or a critical behavior of a model of statistical mechanics that is invariant under the change of distance scales used by the renormalization group.
• In computing, fixed-point arithmetic is a manner of doing arithmetic on computers: a fixed number of decimal (or binary) digits is kept after the decimal point, any remaining digits are rounded; see fixed-point arithmetic.