What is a the other name for burger sauce?

There isn't really a "formal" other name for burger sauce. It's often referred to by its ingredients, like:

* Thousand Island dressing: This is a very common name for burger sauce, especially in the US.

* Special sauce: This term is often used for a specific burger sauce recipe, particularly associated with the Big Mac.

* Burger relish: This can refer to a burger sauce that is more relish-like and tangy.

* Burger dressing: A generic term for any sauce used on a burger.

Ultimately, the "other name" for burger sauce depends on the specific recipe and where you are.