Comparison Isomorphism

I'm looking back into my instructor's notes on category theory, where I came across the following sentence:

Just as there are unique comparison isomorphisms between universal elements, so too are there such isomorphisms between terminal objects (and by essentially the same argument).

What does "comparison isomorphism" mean in this context? I can't find this terminology elsewhere in the notes. I did see a few instances where the term is used in Category Theory in Context, but the author did not give a precise definition for the term as well. Thanks!

In general the term "comparison map" comes up when you have a universal object $x$ satisfying a property $P$, so that for any other object $y$ satisfying $P$ there is a canonical map $x \to y$ (or perhaps the other way): the map $x \to y$ would be a comparison map.

In your case, when $x$ and $x'$ are both terminal objects of a category $\mathcal{C}$ the universal property of terminal objects in particular yields unique (comparison) morphisms $x \to x'$ and $x' \to x$, and the uniqueness in the statement of the universal property implies that these morphisms are mutually inverse: hence, comparison isomorphisms.