bilinear

Etymology

From bi- + linear.

adj

1. (linear algebra, of a function in two variables) Linear (preserving linear combinations) in each variable.
   The function f(x,y)=xy is bilinear, because f(ax+bu,y)=af(x,y)+bf(u,y) and f(x,ay+bv)=af(x,y)+bf(x,v) for all values.
2. (complex analysis, physics, engineering) Of or pertaining to a Möbius transformation (type of conformal map representable as the ratio of two linear functions).
   bilinear isotropic hardening

noun

1. (linear algebra) A bilinear function.