The story
First reported by William E. Caswell in 1974, and later used by Banks and Zaks in their analysis of the phase structure of vector-like gauge theories with massless fermions.
Etymology from Wiktionary, CC BY-SA 4.0.
Banks-Zaks fixed point
Today it means: In quantum chromodynamics with massless flavours, where the number of flavours is sufficiently small (i.e. small enough to guarantee asymptotic freedom, depending on the number of colours), an interacting conformal fixed point of the renormalization group where the value of the coupling is less than one (i.e. one can perform perturbation theory in weak coupling). Full definition →