discriminator

noun

1. 1

   A person who discriminates or differentiates.

2. 2

   A test or variable, etc. that serves to distinguish between different things.

   “Colour is not an effective discriminator when it comes to the spiciness of food.”

3. 3

   Any of several electronic devices that convert some property of a signal into an amplitude whose value is proportional to the difference between the value of the input signal and that of a standard.

4. 4

   A feature of the seller's offering that differs from a competitor's offering and is important to the buyer in question.