Like some mathematical functions

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Bilinear \Bi*lin"e*ar\, a. (Math.) Of, pertaining to, or included by, two lines; as, bilinear co["o]rdinates.

WordNet Word definitions in WordNet
adj. linear with respect to each of two variables or positions

Wiktionary Word definitions in Wiktionary
a. 1 (context mathematics of a function in two variables English) linear (preserving linear combinations) in each variable. 2 (context physics English) Relating to or consisting of two linear functions. n. (context maths English) A bilinear function

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
also bi-linear , 1851, from bi- + linear . Related: Bilinearly ; bilinearity .

Wikipedia Word definitions in Wikipedia
Bilinear may refer to: Bilinear sampling (also called "Bilinear filtering"), a method in computer graphics for choosing the color of a texture Bilinear form Bilinear interpolation Bilinear map , a type of mathematical function between vector spaces Bilinear ...