"Bilinear" is a mathematical term for something being linear in each variable.

A bilinearization is a process which makes a mathematical function bilinear.

it amplifies both the incomeing and outgoing signals on CB radios

A bilinear form is a function of two arguments from the same vector space which maps onto a field of scalars, which acts like a linear form with respect ot either one of its arguments when the other one is held constant.

Bilinear S-N curve theory is a fatigue life prediction model that considers two different slopes of the stress-life curve to account for the crack initiation and crack propagation phases of fatigue failure. The model assumes that different materials have different fatigue behaviors and can be accurately described by two linear segments. It helps in estimating the number of cycles to failure under alternating stress conditions.